ah, so it's cases you're having problems with. good luck with that then. personally i think cases are fucking retarded, but it is what it is.
the only tip i can give you is to remember that once upon a time english had cases too and there are leftovers that you could use to help you understand polish sentence structure.
like for example "whom". that's the accusative case i believe. there is literally no reason that saying "who are you talking about" would be wrong, but to be gramatically correct, you have to say "whom are you talking about", because the person is the object of the sentence.
or for example how in english you say "the vampire diaries" or "the gorsuch file". that structure is 100% a leftover from cases. i think it's the genitive case, but i'm not sure.if you were to use the rules of an analyitical language (language without cases, for simplicity's sake) such as english, you'd have to say "the diaries of the vampires".
try to notice and pay attention to such leftovers in english and maybe that'll help you understand polish sentence structure better.