All I did was to insert the CD [or is it a DVD] and clicked where a click was required. You are correct about two computers; however, when I tried to load it on our 3rd Mac machine, it told me that was unacceptable.
FYI: We have two iMac machines and one laptop in our house [all Mac's].
There is an activate/deactivate function that should allow you to have it installed on 3 or more, but only workable on 2. You have to be careful to do the deactivate before uninstalling CS2/3/4/5/etc or you will run into issues.