Does kissing come naturally?
It really depends on the situation. From the fact you put this question up, I assume you've never kissed anyone romantically before. It really should, but if you're worried, watch a few kissy movies and/or try the following.
Kisses with no tongue are simple: just keep your lips slightly pursed and push them up against theirs. Hugging at this point is encouraged, but not so closely as to impede the romance.