Hello there; You do not need to assign any supports after two columns have entered 1 beam. The red dot symbolizes the node and if only the red dot is visible, the node is fixed. So it transfers torque. Connections that do not transmit torque are hinged, they are not fixed, you have wrong information about that. If you want to create a fixed joint point, do not make any intervention by entering 2 columns and 1 beam. Analyze. As a result of the analysis, if you switch to the right-click analysis view section effects tab on the perspective screen, you will see moments at the nodal points where the beam is connected in the moment diagram under vertical loads. If you want to make a hinged connection, you can enter the properties of the beam and mark the i and j ends for M2 and M3 from the freedoms sub-tab. If you look at the cross-section effects after the analysis, you can see that the moment at the beam nodal points is 0.