SentryHome Household Flea & Tick Spray (16 oz)

So I purchased this product for a quick fix, it helped that it was on sale. The directions are more of a warning than a step by step list on how to use it. I've noticed my carpets aren't swarming with as many fleas as it was when a roommate brought home a stray... but I'm still unclear how much to spray per area on the carpet and this product doesn't have any tips or comments on use. Like will it still work if I don't spray every square inch? Should I move my couch and spray under there? Does it work with leather? Do I have to wash throw pillows after the vapors and smell wear off? I NEED DETAILS AND ANSWERS! Lol

All in all I got a great discount on top of a sale and paid $11 so I can't complain too much. On the other hand the full retail price is about $30 give or take so it should work better than I'm seeing, I also don't know if I'm even using enough..