kimmygirl_13_20 said:
I am a songwriter! I want to put drums in most of my songs!!! But I don't know when I should put drums into my songs? Can anybody assist me???
You can do entire songs without one shred of percussion, though it's pretty rare these days. The trick is in using percussion tastefully in ways that complement the rest of the song.
I find that it is usually distracting to have no percussion and then throw it in the listener's face, but that doesn't mean that you need to use the kit all the time. It's amazing how much you can get out of just a suspended cymbal(either a ride with sticks or a crash with mallets) and rim shots or stick clicks. Then bring in the kick and snare on the first chorus or when the vocals come in or at whatever point where the feel suddenly starts to be more driving... or don't bring them in at all, depending on the piece.
I have entire songs that use nothing more than a set of congas, wind chimes, and suspended cymbal rolls. It suits the mood of those songs. On the other hand, for a driving rock ballad, I like a kit with -lots- of crash cymbals.

For something with a slow feel, you might live on the ride cymbal, hat, kick, and maybe the toms and never touch the snare (or use just the rim).
Hand percussion is your friend. Get a shaker (or Eggz or both) and a tambourine if you don't already have them, and get comfortable with them. (Remember, for maximum control, playing shaker is all in the wrist, not the arm.) They can add variety, as can bongos or congas (though the latter costs enough that it probably makes more sense to do the former).
Sorry for rambling.
Or were you asking whether to lay the drum tracks down first, last, or somewhere in-between?