The Group Block provides a way of grouping multiple blocks together. This can be handy if you want to add some custom styles to a certain section of blocks within your page, or even if you simply want to add a background colour to a group of multiple blocks.
After adding a Group Block, you're able to add whatever blocks you want, into this block, such as Headings, Paragraphs or Image Blocks,
just to name a few.
Once you've added your content to your block, there are further options available in the Settings Sidebar such as being able to select the background colour for your group of blocks.