This video shows how to install a dimmer switch in an Outdoors RV 280KVS travel trailer, replacing the existing on/off switch. I replaced the switches for the lights over our bed and the switch over our recliners.

You can find the parts needed on Amazon:

12VDC Dimmer Switch: https://smile.amazon.com/gp/product/B...

WAGO Lever Nuts Wire Connector Assortment:
https://smile.amazon.com/gp/product/B...