the reason it's so hard is the song contains a thousand billion different sounds and instruments... i don't know how to really strip it down and yet make it heartfelt and cool, because in my head the trumpet sounds really really good
just start doing it. you might not feel like you know what you're really doing until you've done 50 to 100 songs. but you will learn how to do it, automatically, just from experience. if you can get over the feeling of confusion you will have for the first ones. then again, confused music is not a crime