Add Custom Ringtone to Windows App

Already googled this and the only page I can find is this one (https://support.ringcentral.com/article-v2/RingCentral-Phone-Adding-New-Ringtone.html?brand=RC_US&product=RingCentral_Phone&language=en_US), but it doesn't line up to the Windows Desktop App, there is no option to add a ringtone. I find all of the built in ringtones so jarring and would like to add a new one.