Blastopast: GRAW demo clue for a clueless wonder?

Blasty from ye past-y…

So I just got my 360. I heard a lot about GRAW way back when. Fired up the GRAW demo and promptly got my ass shot all to shit. I landed, rounded a corner, took out a couple guys, moved across a square, saw some more guys down the next street (closer to the objective), and couldn’t seem to find a good roadway to get a crossfire on them. So I tried to run up to a pickup and blam, I’m dead.

Pretend I’m a complete moron at this kind of game (OK, don’t pretend – I never got very far into Full Spectrum Warrior, and the last tactical game I played before that was the ORIGINAL Rainbow Six!), and walk me through the demo. What should I do to keep myself and my guys alive?