Basically, "scenting" is rubbing or dipping the mouse on/in something that smells more appealing to a snake. A few different ones you can try are dipping in chicken or tuna broth, rubbing on dirty mouse bedding (to make it smell stronger--I'm talking about a frozen/thaw pinky here, though, as live pinkies usually have a stronger smell), or rubbing on a native/"feeder" lizard like an anole (beardies usually don't have the right smell, so while worth a try, there's no guarantee it will work).
The first thing to try is, of course, to simply offer a plain pinky mouse. Either get one frozen or thaw it out, or try a live one. Whichever you prefer. I prefer frozen because some snakes can be a real pain switching from live to frozen, but live might give you a better chance of him taking it.
Lizard-scenting is generally regarded as one of the last resorts, as snakes that naturally eat lizards very easily get "stuck" on the taste and don't want anything else (aka, you'd have to maintain an anole, or whatever, to scent the mouse on every week). The VERY last resort is to use an actual lizard, because, quite frankly, they're a little hard to come by and tend to be loaded with parasites. However, lizard-scenting is usually the best guarantee of success with king snakes and related species (without resorting to whole lizards).
Hope this helps clear things up a little. And, remember, if you really want to insist on keeping the snake, RESEARCH, RESEARCH, RESEARCH! Just because their care is more simple does NOT mean you shouldn't put just as much effort (if not more) into researching your snake's care as you did into researching your beardie's care. Always, always, ALWAYS research the care of ANY animal (even dogs and cats!) thoroughly BEFORE deciding to get/keep that animal.
I'm going to say that again, to stress just how important it is: RESEARCH, RESEARCH, RESEARCH!!! Read as MANY Prairie king care sheets as you can find!