It’s a difficult book, frankly.
Probably one thing you need to do is to read the earlier works first: the short stories, and The Portrait of the Artist, to familiarize yourself with the background and charaters.
And if you haven’t already done so, you should read Homer’s Odyssey, which it plays games with. No harm doing that, since The Odyssey is a wonderful work in itself—lots more fun than The Iliad.
I contrast that with my reading of Mann's The Magic Mountain which I read as a youth, more than 50 years ago. It wasn't an assignment -- it was recommended by a friend and I just started reading it without knowing anything about Thomas Mann or doing any background research. It's a good yarn with three-dimensional characters.
Just a few years ago, I picked it up again and it was like an old friend. With some age (and hopefully some added wisdom), it was even more enjoyable the second time around. I then enthusiastically recommended The Magic Mountain to a colleague who started reading it and then quit after less than 50 pages, pronouncing it boring.