1. During the first wave let the conscripts kill your pioneers.
2. Leave the game running (do not alt-tab or pause game) for about half an hour (or even more if you want/need).
3. Go do something productive - read a book, have a cup of tea, clean the room or something (i know it's hardest part)
4. Go back to the game when you decide that you have enough resources.
5. Create 2 pioneers squads and 1 mortar team (do not kill conscripts just yet!)
6. With mortar team destroy 2 bridges
6a. Build a lot of bunkers with MG on each side
6b. Build remaining base buildings
7. When you decide that you're prepared enough - build tanks, mortar truck, some panzergranadiers and maybe some AT cannons and kill conscripts from the first wave.
8. Have a fun with the rest of the mission!