Reader's Digest condensed version:
Winter time. Snow on the roof.
Neighbor headed to work 4:30 AM & saw my chimney was on fire, car horn & loudly knocking on my door, said "Chimney Fire! ".
Now I'm wide awake fast . Turned the stove air intake OFF.
Threw on insulated coveralls, no shoes. Saw red hot glowing all over the chimney cap.
Ran to the garage; grabbed a garden hose hooked it up grabbed a ladder & sprayed it from the top. Was moving pretty fast. ( Younger then )
Rip the attic access door off,checked the attic where the pipe went thru, no smoke or signs of burning.
Bought an 8" chimney brush that day & cleaned it.
Took a while, brush wouldn't go in the pipe very easy, got several gallons. Some 3/8" thick. Looked like boiled tar but hard like coal.
Had it inspected, all OK. Nothing burnt in the attic. Was a good install. Got lucky.
Had left the stove on high before going to bed because the wood wasn't burning well. (now I say DUH! )
Started cleaning it every 6 to 8 weeks after that, always got lots of creo. Thought that was normal.
Now I know what wet wood & slow cool burns will do.
1st, turn the air intake to the stove off. Starve the fire of air. Spray the roof with water in case hot ember are on the roof.
Get the creo fire out out & then clean the chimney

Inspect chimney often & Start burning drier wood soon!