How do I add a railing to an existing gap?

I have to add a railing or wall the empty gap on the right side of the stairs but no matter how I word it, it only replaces the existing railing on the walled side of the stairs. What do I use, and how do I word it so it’ll show me a new railing or even a wall on the empty side of the stairs?

Hi Christopher,

Do you have a picture from the bottom?
These pictures are both looking down from above which is a very rare camera angle that the AI doesnt really understand because its mostly trained on pictures looking at things horizontally.