It depends on how your staff are entered into your system. If they are in one particular homeroom then you search by that homeroom code to bring the list of teachers up. If not, and you have a Client Type of "Teacher" or "Staff" which you have used on their records, then you can search by Client Type to find them. If neither of those are how you have them setup, then you may need to select them individually and then use the SUBSET to bring them all together.
Once you have the list of teachers the labels can be printed as you would for your students. If you need further information, you may want to send an email to L4U.Support@powerschool.com where an agent can schedule a call back with you to review your setup.