Time Shift Option

Quick question if I may?

I've seen the Timeshift option on the settings on the inner portal, I've tried to set it up using a usb stick formatted to FAT32. I have set the time to 1 hour and to use it press 'pause'.
There is a symbol which has appeared next to the programmes (clock with an arrow around it).
But when I press pause nothing happens - any tips?

Cheers