answer:There are a few critical things for installing a laminate floor. Whatever you install it on has to be perfectly flat or it will break at the seems. It also does not hold up well to moisture (it’s basically heavy-duty cardboard with a photograph of wood ontop, coated with a very hard and transparent protective layer. Just like getting a cardboard box wet is a bad idea, so is getting your laminate floor wet. You should leave gaps around the edges to the wall (I think it’s like a quarter or an eighth of an inch). This allows the floor to expand and contract in summer/winter. You should also acclimate the laminate to your house’s temperature and humidity before installing. You do this by slicing open the plastic packaging of every box of laminate and letting it “breath” for a while (I think it’s like 24–48 hours or something like that), prior to installing it. As far as underlayment goes, I just bought these rolls of foam they sell. It’s a moisture barrier and it prevents the “clacking” sound when walking on it, making it sound more natural. You just roll them out onto your floor and tape along the seems. The laminate just rests ontop. You shouldn’t have to buy the kind with the underlayment attached. I think it’s cheaper to buy the rolls—check with the sales guy. Also note that the coating on laminate floors will tear up saw blades. You might want to buy one just for this job and then throw it out when you’re done. One more thing to add is that you have to work from one direction across. Think carefully about where the best place to start will be, because there can be tricky corners to deal with and you don’t want to figure that out after you laid out 70% of the floor.