What is the process of your condo association putting a lien on your property if your mortgage is paid up?

The association must notify you of assessments due, and afford you a payment plan to pay your assessments. Usually, these are monthly payments you make to the association.
When you don't pay your assessments, the association may file a lien on your title.

What you owe to the association is not related to your mortgage. Your mortgage is a financial relationship that you have with your bank. Your assessments pay for the operation of the community, and you are obligated to pay your assessments.

Read your governing documents to determine and understand your financial responsibilities to the association.