no... you make a custom hero, name it random. then make an array variable for the heros.
units sells unit
unit type of sold unit = random hero
create one variable(random number between one and number of heros defined) at xxx and face xxx.
also, define the variable:
hero1 = paladin
etc..
and make sure the array is large enuf to compensate for the heros.
i.e. if their are 12 heros, the array must be 12, and the random number is between 1 and 12.
your tutorial says nothing about random hero
edit: give the random hero the ? icon, so people will understand wat it is.