When you are on Edit Screen of Page or Post, You can add any About block from Gutentor..
- Click on the + icon inside a circle at the top left corner of the editor.
- Choose any blocks there or type About in the option in the search box.
- Click on Gutentor About Block and Start Adding content and design it.
You can also add predefined About Block from Template Library
- At the top right you will find the blue button named Template Library.
- Click on it and you will find the option Blocks. Select Blocks
- On the Search Field You can search using keywords About or Select About on the options