In order to Enter An Installment Payment or a Balance Payment,
In the top tabs click "Enter Rent Payment"

Then Search for the Tenant for whom you want to enter the Balance Payment

Then Click "Enter Payment" in the column of that Tenant

This takes you to the form for entering the rent payment

On This page scroll down to the bottom where you will see a table of all payments made by this client

Look for the Balance Amount on the payment you want to clear

Click on the Balance

Then on the Next Page, just click the button Submit

The Balance will be cleared