The first Soviet mission is an introduction to their new hero unit, for the most part. It also allows new players to the genre to get used to making units in Red Alert 3. When Natasha lands, take her toward the fortress. Her weapon can hit multiple infantry at once, in a line. I recommend you use the attack-move order by pressing 'A' then right clicking on the ground. Natasha's not quite as fast as Tanya at killing infantry, but she can blow up enemy structures from a distance by calling in an airstrike. Once the guards are down, you'll use an air strike on the front gate. The game will automatically choose when it's appropriate to call the air strike when you right click a target. For vehicles, she will always use an airstrike as her main weapon is specifically for infantry.

Once inside the fortress, clear out the remaining Empire of the Rising Sun infantry and you'll gain control of the barracks and your co-commander will gain battle control. You will gain a new objective to train five flak troopers. Do so, and garrison them (right click a building) to the southwest of the fortress. From there, they can shoot enemy aircraft as they come. Natasha can handle herself just fine against the Rising Sun tanks that come through the east gate, but you could build a few more flak troopers and switch them to mine weapons by pressing 'F' to lend her a hand. The range on the thrown mines is practically melee, but they do good damage.

After a while, the Rising Sun land attacks will cease, and you'll be given a bullfrog to launch Natasha across the channel. Place her inside the vehicle then use its secondary ability to fire her, and she'll land with a parachute. Kill all the infantry that are trying to destroy the hermitage, then send her back across with the second bullfrog.

The Empire will send battleships to attack the hermitage from afar. You'll now need to methodically destroy them with Natasha while protecting the hermitage with infantry. You have plenty of money. Use it to build some flak troopers and conscripts. Flak troopers should be set to use mines so they can destroy any empire tanks quickly. While using Natasha, be careful and avoid the tengu that escort the ships. They can hurt infantry, but most of the time Natasha can kill the battleships from afar without attracting their attention. Destroy all the battleships and the mission is complete.