SEARCHING:
Open the extension (cmd + shift + K) and start searching for the tab, bookmark, or history you're looking for. It's a fuzzy search, so no need to be perfect.
PRO TIP: Read this to learn how you can change the shortcut to open the extension.

JUMPING AROUND:
After you've found the item that you want press enter or click to focus or open it.
‍PRO TIP: The most recently accessed tab will be auto-highlighted when you open Tabb. Immediately press enter to switch back to it. I promise you'll end up doing this all the time.

SELECTIONS:
cmd + click will select items in Tabb. Use your selections to open/close many things at once, or to group related tabs for browsing later.
‍PRO TIP: No need to click every item, dragging to select many items at a time works too.

SAVING GROUPS:
Click the "Add to Group" prompt after you have a selection, and save the items to a new group, or an existing one. Don't worry about making your group perfect the first time. You can add to them later, or delete things you didn't mean to save.

USING GROUPS:
Press tab or click the view toggle icon in the top-left to see your list of groups. Search for the group you're looking for and hit enter. You can open the items of the saved group to your current window, or in a new one.
PRO TIP: In addition to being handy to for saving stuff you want to peruse later, groups are extremely useful for context switching between different work tasks, or school assignments, etc.