How to make a three level stadium?

[beatlesnews_PSN]

I want to make a three level stadium from scratch rather than copy one and improve on it. How do you add levels? I'm finding if you click on a previous item, it only lets you replace that item and not add to it. Or am I missing something?

[Styxx22_PSN]

Select plaza level away from the stadium, hold L1 and move the left stick up to raise it and place on top of the previous level. I think it is L1. Need the controller in my hand