Warning: In order to be able to perform the following steps, your sturmpioneer must have a FlaK 41 construction kit in its inventory. By default sturmpioneers are deployed with such kit, but for any reason it is missing, you won't be able to complete the tutorial.
1. Open the "Use Item" menu clicking the gear icon
2. Click the FlaK 41 icon
3. Drag in the direction you want to orient the FlaK 41
4. Enjoy blowing up tanks