Where this is not possible due to storage limitations, for example if you are using your phone or a mobile device, then instead open the CGP study guide in a separate tab or window - you can do this by right clicking and selecting 'open in new tab/new window' or by clicking on the arrow in the corner of the booklet on the page, as well as the arrow in the corner of the CD tracks folder below.
For most students the .mp3 files will be sufficient rather than the .ogg format