@Brwl - Hello! If you're talking about the live game you can't you would only be able to play any workshop items if the devs add it to their updates. If you're interested in testing the skin out in test build, you need to download Depth SDK (depth editor on steam,) find the files you downloaded from the workshop and slap them in the right folder and launch the test version of Depth.
I made a video a few month ago to tackle this if its about you wanna test shark skins out - Hope it helps =)
https://youtu.be/cguLb15mTs4

Oh i want a ma with white water

RGB shark Niceeee

well it definitely looks like the fish

The pattern is special XD
If people knew how I made it XD

love the colors and patterning c:

YAS