Hey,
First: practice! At least once before you go out, even if it's just in your living room. Better to try in your backyard with gloves on though. Your instructor will probably also be used to helping people out, since for a lot of people their first tour is on an avy course.
I have BD skins as well, and they're not too hard to put on. I have my mesh sheet cut in half, and I fold each skin in half around the sheet instead of having one stuck to each side, so that I can deal with one at a time. I usually keep mine in my pack, but if it's really cold I'll shove them in my jacket, making me look like a snowman, to keep them warm. I prefer them in my pack - less bulk in front, and not in the way of getting to my beacon if I need to.
When taking them on or off:
try to keep them out of the snow or from sticking to anything fuzzy. Keep that glue clean!
To put them on:
Stick your ski tail-down in the snow. Take one skin off the mesh sheet (or, if you have them on separate sheets, you can take the mesh off as you stick the skin to the ski). Hook the tip loop over the tip of the ski, and align the skin with the ski edges. Then just press it onto the ski, working your way down, keeping it aligned. When you get low enough, flip the ski over (tip into the snow) and keep going. When you get to the tail, flip the camming piece over the tail. Run your hand down the skin to make sure it's stuck, and you're done! It'll take less time to get it aligned the more you practice.
https://vimeo.com/1722104
To take them off:
Take your skis off. Put them tip-down in the snow. Pull the tail piece back over to the base-side of the ski, and then just pull! Flip the ski over (tail down in the snow), and keep pulling. When the skin's off, either stick it to the mesh piece, or fold it in half (stuck to itself) and put it away.
It is possible to take skins off and leave your skis on, but I'd stick to the basics for now. I decided to try that on my first tour this year and my buddy was falling over laughing at me as I failed.
I ended up taking my skis off. Haven't given up yet...I will watch those videos again and keep trying! Maybe in my living room...
I have actually found that my skins can be REALLY hard to take off in the field if i put them on in my living room, but have never had that issue when I've put them on outside. I've only put them on inside once, and they were super-stuck to my skis...naturally when I was trying to pull them off with my skis still on. Not sure if it was because of the temp difference or what. I'm not too worried...usually I'm going to be putting them on outside.
Hope that helps!
Have fun on your avy course!