Using shared blocks is simple.
To open the block, tap on the arrow to the right.
Items in this block are now accessible.
If the block has been set to be repeatable, simply tap on the "+" (1) to add another instance of it. The block number (2) is shown in blue.
A second block is created.
You can repeat the operation as many times as the setting allows. Once the maximum number is reached, you no longer have access to the "+".
To delete one or more blocks you added, tap on the "x"
Result after deleting block # 3
You can also add a block that was not included in the report using the "Add shared block" button.
A popup appears to let you choose the block to add.
Choose your block and tap the "Confirm" button
The new block is then added. You can also repeat (1) or delete (2).