Ive read a couple places that players who understand ICM will be immensly profitable ...can anyone please try to explain this...i have a general idea but probably need more technical advice..

immensely profitable hmmm...it could be true for an individual hand but even the best players have fairly low ROIs in medium+ stakes.

Anyways, ICM is most important on the 9-man bubble, ie when 4 players are left. This is because the payout jump from $0 to 3rd is huge.

Basically what ICM 'says' (only with HH we can give better advice)

1) play very tight when you can go broke
2) shove/raise lightly when you have a big stack