Build up your empire and beat other players
As is common in this genre, in order to improve your empire, you'll need to complete missions. After you complete each mission, you'll obtain resources for construction and recruiting units. You're going to need a lot of manpower in order to win.
In War and Magic, the combat system is very similar to the classic 'Heroes of Might and Magic'. The more units you have, the stronger your squad is; meaning: more damage is inflicted on your enemies. Plus, you're going to need to take into account that you can equip your hero with different weapons, armor and objects to improve his skills. Inevitably, your hero's strong points are reflected in his troops.
War and Magic is an SRPG with nice visuals and a much deeper combat system than other titles within this same genre.