Yes, smear it on and let it dry. Couldn't be simpler.
If the hole is large, you can cut a scrap from another drybag and glue it on (glue on the bag and on the scrap then smear over top of the patch after you put it over the hole).
I love silicone based sealant. I've also used it to fix tarp holes (GE Silicone II - wasn't worried about food safe. Wasn't planning on eating off my tarp anytime soon)