And unlock the hidden quests like the cow suit farmer? If so how do I do this?

the download link isn't working.
Can I get those file somewhere else?

The content of the file is also posted directly on the page, you can just copy it from there.

You could also use DevilutionX for it, it fixes a few bugs related to the extra heros. Here they are enabled from diablo.ini https://github.com/diasurgical/devilutionX/wiki/DevilutionX-diablo.ini-configuration-guide#test-bard0

i realised that i have the command.txt file myself. i uploaded it to google disk for you. here is the link: https://drive.google.com/file/d/1CCsVDnqQ57bxp0aYYRlMmHYywTiZwVKP/view?usp=sharing