With Combine, you can study several sets at one time -- or even create a completely new set comprised of several existing sets.
To get started, go to the set page of the first set you want to add to your combination. Select the More menu, then select Combine.
As you add sets, the titles will show up in the left column of the Combine page. You can also search for sets if you want to add new content.
To start studying your new combination right away, open the dropdown menu below your set titles and select the study mode you want, then select Go. Please note that this will only let you study your combination -- it doesn't save the combination to your account.
To save your combination, select Create a set from the dropdown menu and then select Go.
Once you save your combination from the Create Set page by selecting Create at the top of the page, you'll be good to go! And don't worry -- this won't delete the original sets you combined, it will simply create a new set comprised of all of them.