Using if command to enter digit only if element present

I'm using katalon Recorder to run UAT test cases on a new system we are having developed for us. It involves a user logging into the system first with username, password and random 3 digits of 6 digit pin. How can I use the if command to enter only the digits of the pin that are required, i.e. skip Pin#1 if not present, and enter Pin#2's value etc? I was reading about using ${statusOK}==true but I dont really understand how it functions.

Can anyone help a novice please? Thanks