In age of mythology in the editor section how do you use the set tech status trigger to upgrade units to medium or heavy?

Ok first you must have it so it effects what ever army you are after (i.e 1 for player 1, 2 for player 2,etc.. 0 is for Gaia). Then on the tech drop down bar select the upgrade you are after, you can do this for several different troops on the same trigger. For it to activate make sure that it is set to always on the conditions tab.