The More Blocks section is where you add in new blocks that you can create yourself and you can add on hardware like the Lego We Do and the Pico Board.
Make a block
You can make your own blocks in Scratch by clicking on the New Blocks button.
When you click on the options tab you will get the following option choices for building your own blocks.
When you make a new block, you will see something called Define (example My block.) Add a few of Scratches blocks and then your block will come up.
Adding an Extension
You can use Pico Boards and Lego We Do kits in scratch - click on the picture for more information on how and what you can do!