I can't tell you much abut them, nor if they are wood burning, or multi fuel, but beyond that, the principle is fairly simple. Actually, you may be able to look at the grate to determine it's type. If there's a fairly open grate at the bottom, then it'll be a multifuel.
Put a smoke pellet in them, and see if the chimney's clear. Make sure you have Carbon Monoxide alarms, and then do a simple test with paper and a few bits of kindling, and see if any smoke comes into the room, and then check how much come out of the chimney. If that works, then play safe and get a chimney sweep in. Stoves are fairly simple, and as long as they don't let smoke into the room, and there are no blockages to the chimney, then you should be okay.
