It will be a square panel, usually on the wall, maybe below the stove, or the refer. It may have two quarter turn screws to open it, or if black, just push in on the top and it will open. It will be on the wall where the power cord plugs in from the outside usually, and not too far away from that point.
Now, why do you need to find the fuse panel? What is your problem? The fuses are only there for the DC side of the trailer. The breakers for the AC side of the trailer will be there also.
2012 Ford F250 ext. Cab 4x4
2002 Jeep Wrangler Sahara
2008 Yamaha V-Star 650 Classic
2008 Work and Play 18LT