Infantry
is the only unit that can conquer cities. Other units, when successfully attacking an
enemy city, only damage the city production.
Transports
can carry other units. Move units onto a transport to board it. Right click on a transport
to unload units. Each type of transport is specialized on a certain type of units and has
a limited capacity ... trucks and landing crafts can carry ground units, carriers are for
airforce units. Keep in mind that some units need more space in a transport than others -
a tank in a landing craft occupies twice as much as an infantry man. When a transport is
destroyed in a fight, there is a small chance that some of its boarded units can make it
alive to one of the neighbour tiles. Transports cant board other transports!
Fighters
can only attack airforce units. They cant attack ground or naval forces. Keep in mind that
units in cities can be attacked by any other unit ... so a fighter can attack a tank
stationed in a city.
Submarines
are stealthy. They can only be detected when a friendly unit is moved directly next to
them.