Basically after each job, you go back to your beginning house and sit at the chair. "Wait" for someone to come in (time goes super fast) and someone comes in to give you a job.
Most jobs seem to be "next day" and the NPC giving the job tells you the time frame to go to start the job. You cannot get another job while on one.
Make sure you save though, the game is a little buggy, and I bugged it to where I have a duplicate of myself at the chair... and she won't go away (basically game breaking bug)
(you'll see the NPC in the chair in this pic if your unsure where to get jobs) There are 2 of me, because of a game breaking bug, had to restart ;/