I've imported my bookmarks from another browser, what do I do now?

Click on the side-panel icon top-right.
Select 'Bookmarks' from the dropdown menu at the top.
Go to the 'Imported' folder
Click on the + in the webdock to create a new group for the bookmarks
Right-click on the folder in the bookmarks panel and choose 'open all in new window'
In the new window click on the Spaces icon (circle avatar icon on the right-side of the address bar and select 'Send all tabs to webdock group'.
Select the new group from the dropdown and click on 'Move'.
Boost any tabs that you want to have as apps, or keep them as tabs.

Individual Tabs

First, navigate to the folder where you want the Bookmark to go.
Right-click on the Bookmark and select 'Open in new tab' to add it to that group. From there you can:
Keep it as a tab
Pin the tab to the tabstrip (as in Chrome)
Add is as a Saved item in the App tooltip menu.
You can also drag the tab into the correct group.