quote Jack Phillips

I go through the level up to the point where i go into the building where i hear someone say "Help me, Help me, American." Somebody please tell me where to go next.

Just through a grenade down there and kill anybody. Then go down the stairs from where you heard the person shouting help me. Go forward and you should see a pathway to lead outside the building. When you are outside a bunch of enemies will attack you, keep you Spring field ready and go for the headshots. Now, go at the far right end, and you'll see a machine gun bunker, take it and destroy all the ammo depot on your right, right now quite a lot of enemies will spawn in, try to kill them all as fast as possible because like 15 seconds later, a tank will make through from your right, keep shooting at it from your machine gun bunker and it would eventually die down. Now you would see a gate has been opened at the left side from the machine gun. Take the 2 enemies down here and on your right is a save point. Save your game and go forward to find another machine gun bunker. When you are down here use the machine gun just for a second, then back off and crouch. That is because there are enemies with swords that can just wipe out half your health. They won't even be able to touch you if you have backed of and crouched. All you need to do is kills some of the enemies which i suggest you also use grenades. And after you've killed some enemies, there will be a cut scene.