Each stack that moved to a different tile and is on it's own, is allowed to recruit new markers. The nation table shows what kind of markers a stack of given nation can recruit in a given terrain.
A stack can only recruit one type of marker per
player's round. If a marker
type has a number in front, the stack can recruit up to this number of
markers of that type at
the same time (e.g. 2 warriors, the stack could recruit one or two
warriors) but does not get any compensation if it does not take the full number.
A marker must not not be taken, if the stack would exceed 1000 points after recruitment or if the number of markers would exceed the number of units of that type allowed in a 1000 points Warmaster army. (e.g. a stack can not recruit a General if the stack already contains one).
If the stack lacks a compulsory troop type and that type is available in the tile, the stack has to recruit that type in preference of other types. Should there be more than one compulsary troop type that the stack is lacking being available in the tile, the player can choose which one to recruit (rememeber only one type at a time see above).
A stack does not have to recruit, recruiting is voluntarily.
Recruiting is the way to grow the stacks. The recruitment rules are designed, so that the stacks will always be close to legal Warmaster armies, this will ensure more balanced armies (still there can be a major point difference between the armies (stacks) fighting. To have different troop types available in the different terrain types adds a startegic element and some drama (believe me).