myBook Live with iPad - back up not working

**I have a macbook, an ipad and WD MYBOOK LIVE. The ipad is full so I want to move content to the wd drive. I cant find any instructions of how to this, yet the product page suggests this is a core feature. Please can you point me in the right direction, or offer isntructions of what needs to be done.

In addition, the my drive is failing to back  up my Macbook. A message is repeatedly delivered “disk image could not be mounted”. Ive no idea what this means or what steps i need to take to get this corrected. Again, please advise if you know what needs to be done.

Thanks, Ben**

on the mounting issue:

go to dashboard - settings - utilities  and try reboot - this worked for me