Go to the store page and buy company of heroes and it's standalone dlc.
Then install it.

https://test-steamproxy.haloskins.io/steamstore/app/228200/Company_of_Heroes/

Go to steam store and search for company of heroes mods, make sure you scroll to down and select only mods.
Then click on any of these mods and add them to your library.
Now in your steam library you can click on the mod to install it.

https://test-steamproxy.haloskins.io/steamstore/app/1527290/Company_of_Heroes_Back_to_Basics/
https://test-steamproxy.haloskins.io/steamstore/app/721720/Company_of_Heroes_Battle_of_Crete/
https://test-steamproxy.haloskins.io/steamstore/app/681590/Company_of_Heroes_Blitzkrieg_Mod/
https://test-steamproxy.haloskins.io/steamstore/app/317600/Company_of_Heroes_Eastern_Front/
https://test-steamproxy.haloskins.io/steamstore/app/342370/Europe_at_War/
https://test-steamproxy.haloskins.io/steamstore/app/664260/Company_of_Heroes_Europe_In_Ruins/
https://test-steamproxy.haloskins.io/steamstore/app/547180/Far_East_War/
https://test-steamproxy.haloskins.io/steamstore/app/341300/Modern_Combat/
https://test-steamproxy.haloskins.io/steamstore/app/314420/The_Great_War_1918/


Want even more? you can check out ModDB: https://www.moddb.com/mods?filter=t&kw=&released=&genre=&theme=&players=&timeframe=&game=201&rtx=

Just make sure you click the right download link as the website has a bunch of ads around every corner, even better to use an ad-blocker.

https://test-steamproxy.haloskins.io/sharedfiles/filedetails/?id=3498442654