The basic principle of this strategy is to distract from one way then attack from another.
Let’s say there are three provinces. Province A, province B, and province C. A leads to B and B leads to C.
A-B--C
You have province A and C. The ai has province B. (If you had a fighter patrol above province B you would have found 30 infantry and an armoured car in the province.) You send one artillery piece to attack province B from A. After the first hit you will see 29 infantry and an armoured car going after the artillery piece. Then from province C you send in some guys to take the province while the artillery piece flees from the enemy and goes back to province A. The ai will follow.