flexwatt is pretty straight forward, it looks like the defrost on the rear window in your car and it feels like laminated paper. There's 2 metal strips (one run down each side), you have to scrape a little bit of that laminate off on each strip, to solder your plug wire too, it's alot easier than it sounds.
As far as humidity, you'll have to open them and check them obviously, but it's pretty simple. dampen the vermiculite, then squeese the water out of it by hand and put it in the tubs and your humidity will likely be pretty close. you watch the eggs for dimpling if the humidity is too low, and sweating and mold if the humidity is too high. some people put a tub of water at the bottom of the fridge to help with humidity.