Add it to your server
In your server's .ini file (servertest.ini by default), add these to the existing WorkshopItems= and Mods= lines, separated by a semicolon (;).
WorkshopItems=3661336777;3822632286
Mods=Horse;RoseHorseSkins
These lines include the mod it requires, as its Steam page declares it:
- Horse Mod [B42.20+/MP] ·
Horse
| Workshop item | Subscribers | Declared in |
|---|---|---|
| Rose's Horse Skins and Unicorn Horns3822632286 | 49 | description footer |