Well, if you're starting off by asking how you'd "put flavors in beer," (please take no offense here - there's none intended!) you probably should start out reading some of the stickies here in the beginners section on the basic brewing process, and then look into a couple good beginner's texts like John Palmer's "How to Brew" or Charlie Papazian's "The Complete Joy of Homebrewing." Or, if you're more of a hands-on kind of learner, look for a local homebrew shop and see if they offer classes. Either approach will give you the info you'll need to get your feet wet with homebrewing, and from there you can start to learn more about what actually goes into beer.
You can start out, like many of us have, with extract brews - which allows you to learn the basics of brewing process, cleaning and sanitization, fermenting process, packaging, and such, and build on your equipment to move towards all grain when (and if) you feel you're ready for it. Or, you can dive straight in if you'd like, though at that point you're immediately diving into a lot of variables and, depending on just how you decide to approach it, a fairly significant initial investment in equipment.