In AIM, the interface is simplified, so to get a pinned end on a solid beam, you open the Geometry and draw a line across the end to form an edge on a face. You also put a plane in the center and Split the face so you get an edge in the center to apply the Force.
There is a line at both end faces.
Then in Physics, you Add a Structural condition, and add a Fixed Support at one end but you pick the Edge not the Face. A face can rotate around a fixed edge, but a fixed face can't rotate at all.
Then you Add a second Structural condition, it is the User specified Support, and you Fix the Edge in Y only, and leave X and Z free.