To check in a guest on the TablelistPro mobile app, go to the Reservations tab, tap the reservation, then tap the Check In button.
Select the number of guests (female vs. male vs. unisex) to check in, then press Save. You don't have to check in the whole party at once -- if some arrive later, you can check them in then.
If everyone's there, tap Check In All.
The reservation is now checked in.