Although creating backgrounds is the simplest thing to create based on what we have in 5B.
*Come up with a story
*Come up with your trait, ideal, bond and flaw
*Select 4 items from skills, tools and languages; no more than 2 of each
EDIT: Our Wednesday night game moved from the playtest to a 5B/playtest blend (you could use the playtest if something in 5B did not change it). I did that for backgrounds, letting them choose two of the three given skills in a background, and changed the stat boosts to follow 5B for those races not yet included.