Control the power and navigation of the castle siege devices (Catapult, Trebuchet, Battering Ram) to destroy castle towers and walls and conquer the castles. Every 5 levels, destroy castle walls, and in the final level, destroy castle gates using a Battering Ram. 
It is not that easy. You should conquer the castle as soon as possible. Because the enemy is also attacking your army using catapults and arrow attacks.

Proceed to higher levels and open new maps and devices.
To conquer stronger castles, upgrade your catapults to shoot the longest distance and do more damage to the enemy castle. Every catapult has different features, and for different castles, different catapults are practical to use.
Currently, there are 3 maps, which will be 10 in the upcoming upgrades.
There are two different catapults. The number of catapults will be 10 with the upcoming upgrades.