Best bet is to check your owners manual and follow manufacture directions.  Then, you may still need to put a waterproofing product on.  Once again, follow mnfc instructions.

https://canvascampers.com/inde.....w;down=201

Page 34 of the manual gives cleaning instructions: Brush off loose dirt.  Hose down the canvas.  Use a mild soap such as Lux or Ivory in lukewarm water (<100 degrees F).  Rinse thoroughly to remove soap.  If fabric indicates slight water elakage due to soap, rinse again.  A second alternative is to apply waterproofing, use only  303 High Tech Fabric Guard, or 3M ScotchGuard Fabric Protector (red plaid can).  Note: DO NOT USE DETERGENTS.  Canvas should always be dry when storing camper.