An influence on my views was reading an abridged Bible on my own when I was a child to see what my family’s doctrine actually is and to critically examine the merits of its values and realism. School science textbooks also provided some insight into the physical world and its implications.

A unique element of atheism relative to other religious views is that there isn’t a unifying dogma. Generally, atheists agree on evolution and The Big Bang and just basic science stuff, so some elementary literature or media on those could be a start. However, it’s possible to be an atheist and not believe in these things and to instead believe that everything happens and happened for some non-deistic magic reason or because of some other off-the-wall idiosyncratic theory without scientific backing.

Fundamentally, you should ask yourself if you’re interested in atheism due to doubting the feasibility of deities; or if you’re doubting there being a meaning or purpose to life and the universe; or if you’re doubting that your concept of deities could perform certain actions, such as standing by while tragedy happens (or perhaps you’ve got some other reason?). From there, you can direct yourself to the field of study of your choice: scientific, philosophy, and world religions, respectively, but be sure to branch out into the other two options.