If you go to the “SelectionLists” tab in the bottom right, you can create different selection groups that include the edges or faces you want to constrain for each boundary condition.
If you are selecting edges you’ll need to make sure the selection type dropdown on every list is set to “edges”. You may also want to increase the edge width so that edges are easier to pick.
To use these groups you’ll use the “subdomain_elems” card and then include them in the appropriate boundary condition:
