Freeform sketching - Layers?

Can you help? I really enjoy using Freeform for sketching. One thing I've yet to figure out is how to re-order layers of things that I've sketched so that one Color can go above or below another. Attached are a couple of screenshots of what I've tried. Any tips or advice would be appreciated.

If I try it on my Mac, you right click and it's straightforward to do. Just need to figure out how to do it on my iPad