1. Install the mod using Unity Mod Manager.
2. Goto Steam\steamapps\common\Derail Valley\Mods\DVFPSLimiter
3. Open Settings.json (If you don't have a Settings.json, simply start the game and one will be generated automatically.)
4. Edit the file to your desired settings.

NOTE: Make sure when you edit the file you don't delete any of the special characters like brackets or quotes, they are important.

Example: To make your FPS Limit 75 and don't disable VSYNC.

{
"fpsLimit":75,
"forceVsyncOff":false
}

Example: To make your FPS 120 and disable VSYNC.

{
"fpsLimit":120,
"forceVsyncOff":true
}