T.1 Specifying supports

Click on the lower-left node (N1) to select it. Any other selected items are removed from the current selection set. The node is selected. The node label appears if you have the labeling turned on.
On the Node ribbon tab, select the Fixed tool in the Supports group.

A fixed nodal support type is assigned to this node.
Select the lower-right node (N4).
On the Node ribbon tab, select the Pinned tool in the Supports group.

A pinned nodal support type is assigned to this node.

Tip: You can use the Custom tool in the Supports group to generate any restraint or spring nodal boundary condition necessary.

You can review the nodal boundary conditions by selecting either the Supports tool or the Springs tool in the Nodes group on the Spreadsheet ribbon tab.