How to use DW

For my own use (because it's been a long time since LJ) and others (who might be new to this sort of posting format).

potofsoup 's DW for tumblrites masterpost.

I'm sorry I don't remember who on my read list posted this--I opened it in a new tab, did other things, and when I came back to it I couldn't remember the recommender. Please feel free to take credit in the comments.