Can you link to the book you bought?
You should only need these to get a decent sense of the story:
Keep in mind, the comics are very different from the movies. I haven't seen it yet, but I'd bet that Infinity War is a mix of several comic stories and brand new material.
ComicbookHerald Thanos Reading Order
Thanos Reading Order 1973-1991
Infinity Gauntlet/War Prelude (optional):
Infinity Gauntlet/War (1990-1993):