You got it. Pull the PCV valve out, pull it off completely (this is a good time to replace it, it's only about $5). Follow the instructions on the seafoam can. Slowly pour in 1/3 can, then pour 1/3 in quickly trying to stall out the engine. I doubt you will be able to, but got for it. Once you've dumped that in quickly, have a friend turn off the engine while you are pouring (or pour, then run to the key and turn it off).
EDIT: BTW, the white thing circled in green is your PCV. Don't suck the seafoam through it, pull it off first. Remember to put it back before you start it up after 20min and drive it around.
The goal is to not burn the seafoam out of the pistons, but let it sit in there and dissolve the gunk in there. Wait 20 minutes, then start it up and drive it around a bit, loading the engine as much as you can (floor it and let the revs get high).
I recommend doing this on a deserted road, not my houses. If you havn't done it before, you will get a HUGE cloud of white smoke out the back that will linger. Not cool to do it in the city (believe, me, I did it, I felt bad when a logger started coughing when I rove by).
Also, try putting some in your engine oil 500 miles or so before your oil change. 1/2 a can there, maybe a bit more if it's less than 500 miles til your oil change. You can put in 1/3 or so and leave it to help clean out the engine if you think you have alot of gunk.
Check out there website for more info It is pretty useful stuff. A guy at a local motorcycle shop swears by this stuff. Says he has dumped it into old gunked engines that didn't run at all, and this stuff got them running instead of either completely disassembling/cleaning, or junking them.