FlexBuilder-2023 - Tutorial: basic mobile UI
c.f. https://flexbuilder.ninja/ - this shows building the UI for a mobile game, with various common elements, using the FlexTemplates where appropriate, and showing the integration with UnityUI standard features.
0:19 Create a classic header/body/footer layout using templates
0:26 Manually set the size of an item in the main direction
0:45 Use the template 'background image'
0:56 Add a horizontally-centered TextMeshPro label
1:24 Indent child items to align with the background/frame/border sprites you're using
2:10 Simple z-order / Make an item appear 'behind' another item
2:52 Add a row of buttons with custom images, sizes, and padding
8:35 Auto-resize a TextMeshPro Text/Button that hasn't adjusted to fit the new font-size