How do I change permissions of folders on a hard drive from a booted USB drive

I am trying to save my files on my Hard Drive that has a crashed OS. I created a Bootable USB with Ubuntu and successfully booted.

I can see my folders, but I can't actually open them because I don't have permission.

I tried to do this:

sudo chmod 777 -R Pictures

Where Pictures is the name of the folder I want to change permissions to.

All I want to be able to do is to copy the folders & files from my Hard Drive to my USB drive.

How do I do that?