An Overview Of What Legal Research Involves
There is not a standard reference book for this kind of thing.
Basically, the way legal research works is that you have to know what the legal issues and buzz words and basic structure of all of the relevant substantive and procedural bodies of law relevant to a case are in advance. Then, a lawyer uses that knowledge to pin down authoritative cases, statutes, regulations and court rules to clarify the precise details of the legal framework that the lawyer knows the general outline of. Then, the lawyer uses both this general knowledge and specific legal authority to determine what facts must be developed to prove the correct answer to a question and how to develop those facts within the legal process.
This kind of thing isn't set out in clear organized books. It appears piecemeal over a great many sources, mostly appellate case decisions, that each address only one small part of the overall question.
There is really nothing short of going to law school that can teach you how to effectively spot the legal issues lurking in a particular fact pattern – some of which will be substantive and some of which will be procedural. But, until you know which questions to ask, you can't begin to find the right answers.
This is why most countries that adopt Western style legal systems from scratch usually copy the French or German systems, rather than the American or English legal systems. The barriers to entry are just too high for newcomers to the system.
Sources Of Legal Authority
Unreported Authority
Trial court decisions and a great many appellate decisions are not published, are not binding precedents, and there is no practicable way for a non-lawyer to gain access to them in any case. They are not available even in good-quality law libraries.
Case Reporters
The law relevant to any given case is mostly spread out over dozens or hundreds of published appellate court decisions that are arranged in book form in chronological order in collections of cases called "reporters" that cover absolutely all cases on every subject, in multiple different jurisdictions, in addition to statutes and rules for which there is no way you could know that they are relevant without already knowing about them.
Digests
There are some kinds of legal questions that are covered in what is called a "digest" which is a topically arranged set of headnote summaries of holdings in a case prepared by publishers such as West with annotations to the appellate cases where the decision was reached. But, while a digest can be an effective research tool for some common law topics in disputes involving private parties, it is not a very useful research tool for heavily statutory questions related to government liability and obligations in a particular area. Digests are also often not updated by libraries any longer, because they are expensive to update and most legal research is done with word searches of computerized legal research databases (although this is only useful if you know the right keywords to be asking about). Digests also tend to be unhelpful for answering procedural questions.
Annotated Rules And Statutes
Annotated statutes and court rules can be quite helpful, but only when the statute in question has been litigated at a trial court and then appealed in a case resulting in a reported appellate decision (most appellate decisions are unpublished), and even then, you need to know which statutes and rules are relevant (which is much less obvious than it would superficially seem to be). Also, even then, you have to learn how to find the cases referenced in annotations to a statute or rule to read the full text of the case and you need to know how to confirm that a case that is annotated is still good law.
Law School Textbooks
Even law school textbooks in the relevant subject area are not very useful. Unlike textbooks in other fields, law school text books don't lay out the relevant "black letter law" that governs an area of law and are neither comprehensive nor even consistently correct statements of the current law. Instead, law school textbooks mostly contain excerpts from appellate cases in the relevant subject matter (some of which have since been overturned) which are used as starting points in class discussions about the area of law covered and the actual answer to the questions implicitly associated with these discussion points (but often never actually stated outright), if there even is one (U.S. law school textbooks focus mostly on questions that have not been resolved by the courts in advanced classes), is frequently omitted from the textbook and left as an exercise for the reader.
You Aren't Qualified To Figure This Out
People who represent themselves in this kind of litigation lose something like 95% of the time, and more often when the relevant facts and law are complex, even when they have graduate degrees in unrelated fields and are very smart people.
To use a medical analogy, what you are interested in trying to do yourself isn't quite brain surgery or a heart transplant, but it is like trying to do a do it yourself C-section, or a root canal, or trying to figure out how to remove a burst appendix by yourself, without killing the patient(s) or leaving them worse off in the process, without having the authority to use prescription drugs in the process.
To use some IT analogies, what you are interested in trying to do yourself isn't quite as difficult as writing your own operating system in machine code from scratch, but it is far more difficult than assembling a computer from parts or writing a mobile app. It is perhaps comparable in difficulty to setting up an interactive real time web portal that connects databases from dozens of databases that are different formats in different organizations written in a computer language you've never used before without a user's manual.
To use an analogy from theology, what you are interested in trying to do yourself isn't quite as difficult as writing a multilingual concordance of the entire Bible and apocryphal and pseudo-epigraphic texts with exhaustive fully cited commentary referencing all known manuscripts in their original language with parallel translations from every available translation. But, it is much harder than figuring out a denomination's doctrine on a point or interpreting scripture from a Bible translated into a language you can read. It is roughly comparable to trying to translate Leviticus from Hebrew into Russian when you don't know how to read Hebrew characters and the only Hebrew-Russian dictionary available to you only has half of the words that appear in that book of the Hebrew Bible in it, and you don't know what Cyrillic characters stand for either, and you have never encountered the Russian language before in your life.
Post Script
These warnings are not out of proprietary interest. I've actually turned down lucrative job offers to work as a lawyer in Texas in the past because I didn't want to live or raise a family in that hell hole.
I'm simply trying to prevent you from experiencing a kind of tragedy that I see routinely as a litigator when I observe parties trying to represent themselves in these kinds of matters when they lack the background of legal knowledge necessary to do so effectively. All too often the people least qualified to do something are the most confident about their ability to do so, and I am trying to provide a third party assessment of how hard it is to be actually qualified to do so in order to prevent you from misjudging what you are qualified to do.
Often people who try to do it themselves had perfectly valid cases, but lose really important and valuable rights because they are unable or unwilling to pay a lawyer to handle the matter correctly for them. It is a sad tragedy when this happens.