Then you can use the trigger i posted.
Create the upgrades you want, add them to the units, set level of upgrades to +1 each time lumber is collected for the player that should have the upgrades.
To add creeps to spawn you could use a loop and an integer variable or just an integer variable.
If you use only an integer variable set it to + 1 each time lumber is collected and on the trigger where the creeps spawn do Create Integer_Variable footman at x facing x
The Integer_Variable is a number so it will create as many footman as the number in the variable.
The Integer_Variable needs to be set to a value because the default value is 0.
For loop its:
For each Integer A from 1 to Integer_Variable
Create 1 footman at x facing x