Assuming he is playing global.
In that case you load move and unload in the same turn.
Since some people have troubles reading the rulebook unloading can be unclear, as the example in older versions is really bad.
Basicaly during 1 turn you can, Load + Move + Unload.
So you can load at your start position, move to the unload position and unload.
Move to the load position, Load cargo, move to the unload position and unload.
The total moves cannot exceed movement of the transport so moves before and after the load get deducted from the units total movement range each turn.
You cannot move after unloading.
Units loaded during the combat move should be unloaded during combat move and cannot be unloaded in non-combat.
The later is especially important if you attempt an invasion but your naval units cannot win and you are forced to retreat, those land units in the transports are then stuck inside ( and are painting a big bullseye on the transports )