If you click onto a runtime you will see a list of your available runtimes based on which GameMaker products you own. If you navigate to (log into your YoYo Account if you're asked to), you will see a list of your currently accessible runtimes.
(If that is the case, you need to follow this FAQ on setting correct file permissions and antivirus settings instead.) You should review your ui.log to confirm it is a download issue you have before proceeding with this guide because if your issue is actually that your runtime installation fails due to file write permissions or an overly-sensitive antivirus client on your machine, downloading the runtimes manually via this system will not change that outcome and the installation will still fail.
There is the ability for you to manually download GameMaker runtimes for cases when restricted internet access or very slow speeds will cause the automatic download attempt within the IDE to have issues.
