Help me plz

hi all, i belive u all tried cube defence, but how do u make this board for selction of difficulty ? and how can i make the units increase - decrease in hp ?

plz help me.. ( i need theese sorts of triggers for my new map )

i forgot....

a dialog is that box thing. and when u spawn units, use a loop

foreatch intiger between 1 and 10 spawn 1 CREEP

unit- set last created units hp to BLA%