Press Sky on your Sky Q remote or select Recordings from the Home screen, then select Downloading.
From there, you can:
Prioritise a download: Can't wait a second longer? Find the show you want to push to the top of the download queue then select Start download or Resume download.
Cancel a download: Changed your mind? Find the show then select Cancel download.
Delete a queued download: Find the show then select Delete.
Pause your download queue: Select Pause queue to pause all downloads (you can’t pause one at a time). To start downloading again, select Resume downloads.