No, you should not skip the sections on EU law.
When the UK gave notice to withdraw from the EU, Parliament was cognitive of the fact that you can't simply repeal decades worth of law in one fell swoop without causing all sorts of chaos and uncertainty in the legal system.
So, pursuant to sections 2 to 7 of the European Union (Withdrawal) Act 2018, they provided that EU law would remain applicable in the UK after the implementation period, subject to some specific rules and exceptions (which I suggest you familiarise yourself with by reading those sections of the Act).
In this way Parliament is free to take its time to pick and choose which specific laws they want to repeal in the coming years / decades.
One important consequence, pursuant to section 6, is the rules of binding precedent have changed in relation to decisions of the European Court, particularly as they concern the Supreme Court.
In summary: you must still learn EU law, but you would be advised to purchase a very recently updated book which takes account of the rules post-implementation period.