How to uninstall DLC?

[SPC (Ret) A. Hawkins]

How do I uninstall SOG Prairie Fire, and keep it from updating on Steam. Hate sitting down to build a mission only to be slapped with a 30 gig update for a DLC.

 

[CW4 M. Jaeger]

Arma launcher ... "DLC" option from menu on upper left, just two items above "Mods" ... just uncheck it from the list of DLCs