From the author's README on Thunderstore

My buddy gave me this hat as a gift several years ago. Thought it'd be a nice addition to the collection. Icon is meshed and masked giving it some depth (Not that it matters being so small),

Install Thats My Ass Bro Stop Trucker Hat

You need ReSkate and your own copy of skate. on Steam.

Open ReSkateLauncher.exe and go to MODS.
Search for Thats My Ass Bro Stop Trucker Hat and click install. The launcher also installs anything it depends on.
Press PLAY. In game, the MODS tab of the ReSkate menu (Insert) turns it on and off.

Or install it by hand: download the .zip and drop it on the launcher window, or unzip it into its own folder in Mods\ beside Skate.exe.

Maps show up in the ReSkate menu's level list. To join a server running a custom map, you need the same map installed. If the game won't load after installing, see known issues.

skatemods doesn't host or review this mod. The download comes straight from Thunderstore. Only install mods you trust, because scripts can run code.