Hi there! Do the controls show up at all? Or are they just not sticking to the top of the screen?
By default, the block toolbar controls will only show up contextually, alongside each selected block. To pin them to the top of the page, there’s an optional “Top Toolbar” mode.
To activate that, open up the ellipsis (…) menu in the upper right side of the post editor. There should be a “Top Toolbar” option that you can select.
Let me know if that helps!