The filterForm it’s a panel level object.
From a design perspective, the filterForm is just like a normal form. What makes it different it’s that the filterForm supports a filter link as a source. In this way, it can filter a business entity.
Inside the filterForm you can add inputs just like in a normal form. The input names are important because they will be used as filters. Besides the inputs, it’s mandatory to have a button with a click event that will call the applyFilter from the filter target business entity.
Exemple of eventClick:
$ self.controller.form.akElm.dynObject.getLink('FILTER:TARGET').controller.applyFilter();