Saving Songs

We currently have a file of Songs downloaded to a "Favourites" file in You tube. Obviously I cannot listen to these songs if not
logged on to You tube

How can I transfer these songs form You tube to a more permanent file either to the hard drive ot to my PC

At the moment my PC does not see any of these files when attached to my tablet. This is because they are only visible when on line

Sorry for rambling on I would like to transfer thsese to my I Pod

Any help would be appreciated

Regards Fred