The next material you need is hops. Hops provide a bitter flavor that balances the sweetness of the malt. Additionally, hops can add spicy floral flavors and aromas to your beer. Many different varieties of hops exist, and they all have different bittering abilities and flavors. Following your recipe is the easiest way to make this decision.
Hops generally come in two forms, whole and pellets.
Both are the same material, but the pellets have been ground up and compressed into the pellet form. Both forms work equally well in creating homebrew. You won't go wrong with either selection. To use the hops, just dump them into the boiling wort, at the time called for in the recipe. The actual hop particles should not be present in the finished beer, so make their removal easy.