Welcome to the boards! I'll try for a helpful response
If you choose to fight your way on foot, never put yourself in the middle of battlefield because then you will get shot at from all sides. Play one side or the other and get used to where you can go, where you can get cover, when to run, when to save your force run, etc. You will more than likely die a few times getting to the first objective (the first CP). However, the easier path is to fight by jumping in the AT-RT (the ostrich looking vehicle...hit the triangle button when you get near it) as soon as you spawn. Then fire away at the advancing droids while moving to the CP you have to capture. You have to get out to capture the CP, though (triangle again), but first clear as much of a buffer zone as you can and KEEP MOVING (otherwise the grenades and other explosives will tear you down). Then, you can use Mundi to run behind the shield (or even jump it if you want to do it the longer way) and do a saber throw to blow it up. I actually prefer to blow up the SECOND shield generator first, then come back to the first one (all from the platform/building of the first CP you captured). Or you can play a trooper--just throw a grenade such that it sticks to it or fire a rocket launcher. Then, run and grab the OTHER AT-RT before someone else does and clear a swath to the next CP. Jump out, run around and take it. Keeping Mundi alive is great for that, but it certainly can be accomplished with a trooper and ducking (circle) and rolling (circle and left joystick) a lot (oh, and firing
Then, if you still have an AT-RT around, you can use a trooper to go take out the two generators of the next objective. Or you can use Mundi if he's still healthy. You can practice with Mundi, BTW, by doing an Instant Action-->Mos Eisley-->Assault mission and play the heroes. Get used to his different powers and abilities (specifically force run while attacking).
Anyways, take out the energy collector (or whatever it is), grab the objective piece, and run like hell back to the ship. Don't try to fight. You should get the blue VICTORY.
I found several links that also helped which may help you (walkthroughs):
google is your friend, too.
Hope that helps.
* SithSpeeder *
(who's 8 year old son got BF2 for Christmas).