Don’t do it in someone else’s game thread. (Just create a new thread like you did this with this thread.)
General Information
Besides that it’s really open to however you want to do it… Someone like to just toss the background information out and look at character concepts (basically no mechanics) some go by first come first serve while others want to pick the best character for there game.
Looks like you are off to a great start already! Welcome to the boards. This very thread is probably enough to get started, and you can edit the title to give a little more info as needed. Often, it would look like this:
Jimmy the Fish's D&D game, recruiting 3-5 players plus alts