Dutch oven cooking should be easy as long as you don't try to force it (Too much, too fast).
You have a 12" without legs? Were they cutoff or is this a dutch oven that was made for oven use? (Is there a charcoal lip on the lid or is it domed? Or is it a combo cooker? Looks like two skillets together.)
Either way you'll need a way to lift it above the coals. One way is with a lid stand (
http://www.amazon.com/Lodge-Original-Finish-Dutch-Stand/dp/B0002LYZNK ) or use a paving stone or rocks.
The secret to not burning stuff is using less coals on bottom, more on top. Also keep the coals closer to the outer edge, so you are heating more metal, more evenly without hotspots in the middle. I've found if you just make a ring on the outer edge, top and bottom, with each coal just touching the next, works pretty well. Lodge has a chart to help:
I don't know how often you use your DO but a well seasoned DO is nearly non-stick. If it hasn't been used in a while you might want to really grease that thing or use parchment paper. Also, if it's just the two of you, a 12" makes a lot of food. You might want to bring some smaller 8" baking pans to fit inside. (8" is a perfect size for Jiffy mixes)
As for telling when it's done. "If it smells done, it's done. If it smells burnt, it's burnt. If you can't smell it, it's not done." Cee Dub "Butch" Welch. (Has some very good books on DO cooking.) But I also like Byron's Dutch oven page
http://papadutch.home.comcast.net/~papadutch/Some other tools that make DO cooking easier. Tongs or a garden trowel to move coals. Welders gloves. A wisk broom (I use a wide paint brush) for ashes. And a lid lifter, Mair makes the best.
Good luck. Where did you get drawn?
