Add a railing to a stair that has already been placed in the model.
This video demonstrates the following:
When you create a stair by component, you can choose to have a railing created automatically. There may be situations where you want to place a railing on an existing stair or ramp that does not already have a railing.
On the Circulation panel, click the Railing drop-down, and click Place on Host.
For a stair, you can select to position the railing on the treads or the stringers.
In the Type Selector, select the type of railing you wish to place. You can also change the type after the railing is placed.
When you move the cursor over a stair or ramp in the drawing area, the object highlights to indicate it is a valid host. You cannot place a railing on a stair or ramp that already has a railing.
Click to place the railing. Notice that the railing is placed on both sides of the stair and all connections are created automatically.