Where do i find my online key for these games so i can do multiplayer?

If I'm not mistaken, it should be under your Account, open the game and check under "More". You might want to do it through the site and not Galaxy.

thanks had me worryied when i checked under tribe of the east first and found nothing

under more for tribes of the east i have:

assign tags
support
gog downloader links
forum


under more for hammers of fate i have

the above and serial keys and that provides 3 keys for homm5, hammers of fate and tribes of the east