Being the first level, you can expect this to be extremely easy. You begin with Soviet dreadnoughts attacking the statue of liberty. Swim Tanya to each dreadnought and she will destroy it with her C4 charges. The GIs guarding the statue will handle the first wave of infantry attacking the statue, but once Tanya is finished move her up toward the statue to join in guarding it. Once the attackers are finished, a new objective comes in. Get your troops to fort bradley. You shouldn't have much trouble doing this, Tanya can handle large groups of infantry by herself. Just move forward slowly so you don't run her into one of those groups without attacking. She's not invincible.

Once you've reached fort bradley you are given control of the base and its resources. Begin constructing a barracks immediately. Once completed, build some GIs and an engineer. With the GIs you started with, I recommend bringing about 20 men on this mission. Order your engineer to repair the small building next to the bridge. This fixes the bridge and will allow you to invade the Soviet base. You can see most of the base and what you're up against - not much. The metal barrels next to everything are explosive so if your men are ordered to fire upon them, they will detonate damaging surrounding units and structures. Keep your men clear of these, but do blow them up, do this by ordering your men to destroy it while you are still away from it. After the initial infantry guarding the area just after the bridge order your group of infantry to destroy the barrels next to the sentry guns, once one goes down, move to the next. These are the thing which pose the largest threat to your forces on this level. So try to do this quickly to avoid losing many men. There isn't a whole lot of danger here, you can always build more but you can finish this without many losses. Once destroyed, move your infantry forward and slowly advance through the base, deploying them (with the 'D' hotkey) every once in a while and destroying surrounding buildings. Before you know it, the base is toppled and you are victorious!