How do I record only to the Cloud DVR and not to the X1 Box?

I upgraded to 300 hrs of DVR space, but after extensive searching and talking to techs over the past few days, it appears I cannot use that space. My DVR box storage is close to full, so even though I have used just over 50% of my cloud storage space that I purchased, I can't use more because the box will start deleting recordings if I hit its capacity. (I have old recordings on the box I do not want to lose.)

From what I understand, the only way I can use the storage I am paying for is through recording the excess content only to the cloud. At least one tech said this was possible. This issue? I don't see an option in the app that allows me to choose where to record the content. How can I record only to the cloud (and if I can't, what is the point of cloud storage in the first place if it is limited by box capacity?)