Convert points into unit?
First, make a trigger and decide the event. How will player do that conversion thing, Typing something? Click on Something? or else...
Next, Condition, put POINTS_VARIABLE >= 100
Last, action, set POINTS_VARIABLE = POINTS_VARIABLE - 100; Create footman on specific location.
btw, what do you mean by massive battle in the end of game? A cinematics?
If it's a cin, then maybe you want to do this
ACTION:
For A 1 to X,
if POINTS_VARIABLE >= 100 then create footman
set POINTS_VARIABLE = POINTS_VARIABLE - 100