note taking for main points might help
i used to struggle with memorizing full chapters but when i tok notes of main points for a chapter that usually helped
ideally the chapters of your textbook are organized by sections each with titles and often times bolded or italicized vocabulary words or key items within the chapter. making notes of those things (and sometimes of the examples in the book) can help
as for how to apply that to multiple choice: if things from the test look similar to things you've seen in the book then you've got a better chance of making more informed choices/guesses even if you don't fully remember every detail
as for distractions i think this threads tips could prove useful for finding ways to say focused
some other things that may help is having dedicated time for pure study with timed intervals for breaks whenever you feel like you can't hold focus as well as creating space that leaves out potential distractions or includes things to keep you in the zone like some kind of music or ambience
obviously advice isn't always one size fits all but hopefully it'll help