Question about college loans?

I was given a federal direct parent plus loan. Is this a loan for my parents to take out and pay off? Or can it be a loan for me to pay? My dad says he will not co-sign for any of my college loans (mostly because he doesn't like my major) and so I know he won't take out any loans himself. How exactly do college loans work? I also got a fed. riect unsub student loan. What kind of loan is that? Am I able to get loans from other places like the bank? Can I only get loans from the bank I have a bank account at? I'm going to see if my grandpa will co-sign for my loans but if he says no I won't have anyone else to ask, is there anyway to have a loan without a co-signer? What kinds of loans are the best? What should I know about college loans?