From the author's README on Thunderstore

The Mod originally made by Spargo808 for Session. I have changed some of the textures on the ramps and added a few new features to the Fantasy Factory like the Wild Grinders Funbox, the 'Concrete Wave' and the red mini ramps.

Credits

Original map mod by Spargo808. Map loading and build support: ReSkate and ReSkate Studio by Dingo Shenanigans.

AI-assisted.

Install Fantasy Factory by Spargo808

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

Open ReSkateLauncher.exe and go to MODS.
Search for Fantasy Factory by Spargo808 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.