How do I set up payroll and can I print the patrol checks?

Always read the Guides first. In this case: Guides | Manager. Then ask specific questions, not fundamental guidance.

As to printing, Manager does not print checks.

By establishing the Payslip Items under Settings

Then setting up Employees first then Payslips under the respective tabs

I pay on the 15th and 30th-31st, but I cannot enter this in payroll.

You can set up two recurring pay slips under Settings. One will issue on the 15th, recurring monthly. The other will issue on the 30th, also recurring monthly. I don’t know what will happen in February. You might need to do that one manually or edit it.