Every block can be used from the editor

First, you need to access Pages or Appearance-> Editor.

How to Add Block?

1. Click the + button on top left corner of the editor.

2. A sidebar with block list will appear on the left, choose a block you want to add.

3. The block will be added to the editor.

How to Edit Existing Block?

1. Click on existing block to make it selected.

2. A sidebar on the right will appear and you can edit the block settings

This is just a simple example of adding and editing block. For more detail of each block, visit the block documentation section.