If one had an idea for an invention, but had no ability to make such a device, can you make the "idea" legally yours, insofar as it is specific?
You do not need to able to make it but your application needs to explain how to make it and use it. If a workable implication needs the expertise of a mechanical engineer, you can hire a mechanical engineer. It may turn out that it is impossible, it may turn out that the mechanical engineer needs to be listed as a co-inventor, or it could be straightforward for the engineer to implement your great idea. To ultimately be yours, you need to get one or more granted patents.
Nobody owns “ideas”.
To get a patent you have to describe something in sufficient detail that it could actually be built.