What does it mean to stack and how do i do it

[hellcaster247]

When i play some of the games on the internet the host says stacking is allowed. how do i stack?:shoot

 

[Wing Zero]

UMS or Melee?if it is melee he is just trying to get u in truble in UMS its differnt i gusse

 

[aphextwin]

if ums...... u hotkey the worker (scv, probe, drone) then u "turn lights off" and just build anywhere u want (as long as buildable terrain available), mainly built on top of other buildings.......