Preload steam

I have downloaded aoe 2 DE via steam, thats 12 GB, is there also the texture pack in there or is that an different download? or a dlc or something.

Texture pack comes as a different optional download

where can i find that?

Not sure. Beta testers got their key for that, so maybe you can get it from the store page

Enhanced Graphics DLC is now available on Steam. Apologies for the delay, but you should see it for free on the Steam store page.