Click on the 'raw' button on the right of the listing and then on 'install'. For items that you can't get anywhere else (especially things like meshes), i use a script called universal bypass, which you can install with tampermonkey. Tiberium alliances sinsofomission script pack a script collection for command and conquer:
To install you need to have either tampermonkey or greasemonkey installed (depending on the browser you use).
Cncta soo script pack command and conquer: When i omit that, the js code will enable the submit button. Tamper monkey no script running hi, just a problem with tampermonkey, when i click on it (chrome) it say activated and no script executed, while in the dashboard the script is. Not helpful if the web store will not consider a valid email.