I originally thought there was a function that creates an overlay/shows hidden objects, that can appear on top of each, and that can be closed when interacted with other elements.
So first off, I tried with overlays, but I needed to close the overlays to interact with new objects.
Secondly, I tried to navigate to a new identical page with the buttons designed as the overlay (https://www.figma.com/proto/XgkTZUVrzsMZabLoffgKyM/HF-Sketch?page-id=0%3A1&node-id=61%3A304&viewport=-193%2C-328%2C0.22110208868980408&scaling=min-zoom&starting-point-node-id=0%3A2&show-proto-sidebar=1), but oddly enough in the last step (2 green buttons active), no interaction leads back to the black buttons although I navigated them back by click…?