Memex is a powerful tool that allows you to organize your browsing history, bookmarks, and annotations in a convenient way. By default you have the ability to quickly full-text search what you find, so you have no need to organise things upfront.
However you can organise what you find into Spaces, which are like tags that you can also share and collaboratively curate.
You can organise content into Spaces in 3 ways:
The default keyboard shortcut to create a new Space in Memex is option+c (Mac) or alt+c (Windows & Linux). Simply press these keys simultaneously, and a popup will appear where you can search and add content to those Spaces.
Another way to create a new Space is by using the mini sidebar. Hover over the right side of the screen, and a small sidebar will appear. Click on the Spaces icon, and a popup will appear where you can search, add and create a new Space.
Finally, you can also create a new Space using the popup in the extension menu. Click on the Memex icon in your browser toolbar, and select "Create New Space" from the menu that appears.
