Couple ways to do it. If you slide off the drum, look on the bottom where the two shoes meet. There you will see a adjuster. Turn the adjuster so the shoes are pushed out toward the drum. Test fit the drum, rinse and repeat
This method works good as long as there is not a lip on the edge of the drum.
You can also adjust from the rear of the drum (through the back plate) with a brake adjusting tool but thats a pain in the azz on our cars because of the lower trailing arm bracket is kinda in the way but it can be done.
Side note: If there is a lip on the edge of the drum, You can take a Angle grinder and clean it up. I've done that B4.
Let us know how it goes.