Your current task: Infiltrate the base
The infiltration begins pretty smooth and silent.
After climbing the ladders you will encounter first enemies - try to eliminate them quietly, using knife, and not to trigger the alarm as long as it is possible.
But when you ran into the flamethrower soldier - all the hell will break lose. That is what you should be used to now.
Your current task: Plant the bombs
Soon you will get to control room. The boys' plan is to blow the whole place up. So will have to plant 3 charges.
Get yourself a minigun - it's second attack, turning it into the turret, would be very helpful - and plant some of them on the elevated walkways. Avoid fighting with the bugs - just focus on running, dodging them and planting the bombs.
Your current task: Get out of the base
After the cutscene it's time to get out of this place. Don't worry about lack of weapons - you will find them on your way.
There are lots of broken doors waiting for you. You will also encounter confused soldiers and animals - but they should cause you no problem.
Soon you will get to the "arena" - where the raptors will show up. You will have to kill them all and it is going to be a long fight.
At the end of the party - the doors will open. Get rid of the dilophosaurus and get out of here.