Flodnak, normally you don’t worry about removing the pumpkin’s solid flesh–just the seeds and strings. Some jack-o-lantern carving specialists insist on hollowing out the thing to where it’s the 1" (or even less) thickness mentioned by ejrn, but for Norwegian Newbies, just take the icky parts out. You don’t need the whole globe to be glowing, you just want a candle behind the face.
The only reason to be really meticulous about removing all the goop is if you’re carving your pumpkin way ahead of time. The goop is what rots first, so if you’re carving punkins on October 15, you wanna scrape it out good, get it really dry inside. But hey, Halloween’s tomorrow. You can stop scraping when your “Icky Meter” goes over the redline. 
And, what Delphica said about a flat bottom for the candle–it actually works better to put the candle in something like a jar lid (stick it down with a few drops of melted wax) and then carefully lower the jar lid into the pumpkin. And candle stubs, about 3" long, work better than longer candles. A longer candle is harder to lower into the punkin, and it bumps on the lid and just burns it, and doesn’t provide adequate illumination behind the face.
A pumpkin that has a good solid stem for grabbing the lid is nice, too. Purchase no punkins without handles.
Do you need instructions for how to make a lid? The important thing when cutting jack-o-lanterns, is always to go at right angles to the pumpkin’s flesh. “Go straight in,” is what I tell my kids. “Don’t slant.” So make your lid cuts as “straight-in” at right angles to the pumpkin’s flesh as you can, all the way around. (Draw the line first, with a permanent Magic Marker). Is this making sense? You should end up with a lid that’s a truncated cone. In other words, you don’t just slice the top off the pumpkin like slicing the top off a pineapple. If you do that, the lid won’t stay put, it’ll keep sliding off onto the floor.
Tips for cutting the faces, after you’ve got it hollowed out, and the lid cut: Draw the design first with a Magic Marker (permanent, not washable, because it won’t stick). Then use a kitchen knife with about a 1" blade, and flat, not serrated, and go straight in. Stick with simple geometrical shapes, except for circles. Circles are a bastard to cut, pardon my French. Squares for eyes, triangle for the nose, a very simple “jagged square teeth” kind of jack-o-lantern smile.
Keep the finished Jack-O-Lanterns at cold temperatures, like lower than 60 F., but do not allow to freeze.
All the best to the Little Flodnaks.