How do I use the UF theme's D&D (Drag & Drop functionality)... create sliders in the Upfront Builder with black overlays on top of the images, upon which I can enter white text that utilises Google Fonts?

I updated the Google Fonts API key, but it has yet to integrate (as it said it would automatically) into my theme - I still see the common and ugly fonts Arial, Verdana, etc.

If someone could point me in the right direction with insightful tips as to how to achieve such functionalities, I would be most grateful.

Thanx in advance!