Installing Ubuntu on my First Build! 'Grub Installation Failed'? Help.

I was installing Ubuntu studio 16.04 LTS but as it was installing I got the error message "Grub Installation Failed' and that it won't boot without it. I tried going the 'something else' route to installation, so I had to create the partitions manually, but have no idea how?

I just wanna finish my pc (this is like the 5th thing I had no idea how to fix), so any help woud be appreciated. Thanks.