In the beginning of the mission, you are being held captive in a small farmhouse by German soldiers. While reaching for a fallen comrade's rifle, you are kicked in the face, but before you are killed, a T-34 blows a hole in the side of the building. Then, Reznov emerges through the smoke, along with a new recruit, Chernov. Two of the German soldiers inside are incapacitated, and Reznov kills the other with his PPSH-41. Reznov hands you a Mosin-Nagant, and instructs Chernov to kill the dying Germans. Chernov does not, so Reznov tells Dmitri to. It doesn't matter whether you do or don't. If you do so it's best to just knife them to conserve ammo for your Mosin-Nagant, even if there will be plenty of ammo for it. Inside the hut is an FG-42.
When you exit the farmhouse, you will come across a scene of Soviet T-34s advancing up a path between wheat fields and Russian infantry fighting Germans. Reznov will order the troops to burn the wheat fields. After the field is alight, Germans will run out and try to escape. Don't bother interfering, your allies will kill them for you. Follow Reznov and your allies down the road to river. There you will find a group of Germans defending the ford across it. Note the fact that they will continually reinforce themselves. A bolt action like you Mosin-Nagant would be useless in a situation like this, and your pistol is just a pistol. The FG-42 will spray lead all over, probably killing every enemy who comes up your way. There is a big rock in the middle of the river that Germans just love to hide behind. Throw a Molotov at it to take them out.
When you cross the river, you will have a choice. Do you go left or right? If you go left you'll run into more enemies and you will have to crouch in the trench because it is to short to provide cover from the machine gun. On the flip side, this direction will take you to the underground barracks where you can find an FG-42. The right way provides fewer enemies, several deployable MG-42s, and the high ground. However, there isn't a direct route down to the MG nest. After you have killed the enemies, you will have to run through the trenches and across the field before more spawn. Plus, you won't have ammo for the FG-42. Run down under the bridge and then go up the trench to the big farmhouse. Three enemies will run down, just mow them down.
When you reach the barnhouse, pick up the Panzerschreck, but then quickly bring out the other weapon you carry because picking up the Panzerschreck ques the tanks and infantry to advance. Some Panzerschreck wielding enemies will run up onto the balcony and start taking potshots at your tanks, take them down. Also, if you get too close the tank, the nearby Germans will kill you. Take a shot at the tank nearest you, then get back, or it will blow you up. You will have to stay out of its way for a short while, then it will forget you and you can get in the second and fatal shot. While you wait, take out the other tank that's farther away. Once you have gotten them, run to the trench with the flashing Panzerschreck in front the three-story building. When you reach it, a third tank along with its accompanying infantry will come out. Go prone and crawl up to the very top of the trench so you can just see the tank. Shoot it, then get up and hit it again. Repeat this with the fourth tank, then mop up survivors. Reznov will lead the squad up to the barn. Evidently, there are Germans hiding inside. Just as he tells to soldiers to open the barn doors, those very same doors explode (do not stand directly in front of them. I have tried this. The words "instantaneous vaporization" come to mind) and a tank bursts out. You should take a position at the side of the barn so the moment the tank rolls out you can shoot it, giving you a chance to destroy it before it fires. Your allies should kill all the enemy infantry.
When Reznov opens the door, go and get onto the back of a tank. When you reach the German base, get off and run through the anti-tank barricades. There are more deployable MG-42s here. When you reach the flashing Panzerschreck, crouch and take out the truck full of Germans that drives into the area, then blow up the tower. Wipe out the stragglers, and move through the hole in the fence to the main camp. Another truck full of Germans drives up, but if you fire quickly that can be blown up and an unnecessary firefight avoided. Run down the road to the barricade that blocks you forward progress. Do not dwell here long as there isn't a way through. Instead go to the right and pass in between the tents.
You are now in another clearing. In front of you is a tower which you should destroy with that handy Panzerschreck. There is a German hanging around there who should immediately be eliminated. From here on all you need to do is spam. There is a platform with a squad of Germans on it which you should huck a grenade or two onto. There is a truck next to that which Germans take cover behind, use any extra Panzerschreck rockets you have to destroy it. Then throw all the grenades/molotovs left to you in between the truck and platform between bursts of gunfire (an automatic weapon would be great) until every enemy is dead. Then pass through the platform or around the truck to the road where you see the German convoy trying to escape. Your allies will take care of them, and the mission ends after Reznov gives one of his classic Reznov speeches (kill them all...).