If you want to test the beta version on a test environment, you need to install the latest stable version (download here), then change the update settings and get the beta version through automatic updates.
If you do not see a message about the availability of the beta version, then in Joomla it is enough to simply clear the update cache and repeat the search for updates again.
There is no such button for WordPress, but you can use the Force Update Check for Plugins and Themes plugin to reset the update cache.
Create a download request in a new browser tab and save the beta theme package on your local computer.
This method is not described in the YOOtheme documentation because such handling of your API key may be unsafe. By following this instruction, you take responsibility for keeping your key secret.
Do not distribute or publish your key and/or a link to download the distribution kit anywhere. Discrediting the key may result in blocking your subscription.
The author of the article is not responsible for the possible consequences of using this instruction!