Smart Groups allows you to group ideas by different criteria (categories or dimensions). You can go further by sorting ideas by color, date or number of likes.
The goal is to sort your ideas on the Board according to the defined criteria, without having to go through the Column view (article : What are the different views of a Board?)
1 - Smart Groups access
From your Board, click on sliders, then click on "Smart Groups"
2 - Editing Smart Groups
The Smart Groups editing screen is displayed:
Once you have created your categories and/or dimensions, activate the Smart Groups and click on Save.
3 - Updating Smart Groups
Once Smart Groups are activated, in sliders, click on the "Groups" button on the left side of your Board which allows you to integrate new ideas to existing Groups on the Board.
When you deactivate Smart Groups, ideas do not return to their original location.
To find out more about the Board toolbar, see the resources at this link.