Retrieving specifc cell value for loop

Hello guys,

How can i retrieve specific cell value and loop through.
Ex. Row A1 has got value “3” (this value will be various)
So I would like to put A1 value into the loop. Hope someone will manage to assist me.

Thanks

Set tst = Activesheet.Cells(1,”A”).getValue???
For I = 1 to tst -1
Msgbox(i)  ‘this should pop up like 3,2,1
Next I