It's best to run Paychecks at night, so that all of the points from that day are included. Paychecks can also take up to an hour to generate, so setting Paychecks to run at night ensures they're ready to print in the morning. So if you'd like to pass out Paychecks on Friday, run Paychecks on Thursday night!
Your next Paychecks will run on the day and at the time that you choose.