Q: How the fuck do I begin writing a song
A: you may never know. but that won't stop you from doing it. the only problem is, it will happen when you least expect it, so you need to be lightning quick on the documentation, and also organized. save them for when you are ready to write, then you won't have to worry about starting the song, you'll have many of them started already. which should bring you to your next problem, which is how the heck do you select a song