This Help Resource follows on from the previous Action Designer Help Resources, the Overview, the Open Form and the Open Form / New Object which we recommend you research before continuing with this Help Resource. Much of the configuration of Action Designer is common for each Action Type.
Action Designer allows us to associate objects together, using any of the available association types. The Designer is configured to understand what the two objects are and what the association is.
The attached video demonstrates the configuration of the Add Association Action type, by adding a Button to the same form used to demonstrate the Open From / New Object Action type.