Hello backwoodshunter, first, WELCOME!
CONGRATS on the lil BC and the maxi barrel!! Many of us also have this and its a VERY NICE combo to have!!
PM is short for Private Message. You can "PM" everyone who allows it, (Most do) two ways, clicking send message and typing there name, or easier, when you find there post, you will see some little "icons" beneath there name/handle. If you just hover the curser over them they should tell you what they are.
Like I say, MOST allow PM some allow direct email. His name is "brian56" IIRC and he works for Remington and has helped out many members here getting big green get the crap straight.
Good luck,
CW