I think most of you should find out how to do it, but i explain quickly here.
1- First uninstall AoEO, the official version available on steam.
2- Then Reinstall AoEO from steam library.
3 -Then, never, never launch the game under steam.
4- Download the Celest pack and unzip
5- Select all the files and copy/paste on the steam repertory : normally by default : c:\programFilesx86\steam\steamApps\Common\Age of Empires Online.
6- Rewrite all files that are ask for.
7- Launch the Celest launcher / You will need to register and login after. If you haven't a key for the server it will not work.
Notam : if you launch the sparta launcher, it will be update, and then you need to uninstall the whole game again.
Notam 2 : when you register on the celest server, after you do it, you perhaps need to close the celest launcher, to relog properly.
Thanks a lot for your work.
It was just amazing you succeed in bringing back nearly all the game.
I know for multiplayers, you will need servers. And it is a cost, but a regular one, so should sounds risky. Anyway, if you go on that, best will be to have a kind of year subscritption, just for you and for the players. They know they can play one year if they subscribe.