For admin:

Go to the Child profile page of the particular child you want to put enrollment on the waitlist. Click on the '+' sign next to program/classes on the right-hand side.

An enrollment pop-up will open. Click on 'Enroll Now' on the desired program/class.

Pop-up for program/class will open. Click on the waitlist to put the child on the waitlist for that program/class.

Enrollment for that program/class for that child will be put on the waitlist.