installing new battery cables on '66 barracuda

I really need some help because I've never really spent much time working on cars but I've wanted this car since I was a kid. I've been having trouble with the battery not staying charged. I've replaced the alternator and have a new battery. I was in the process of replacing the battery cables and the positive has more wires coming out of it then the new cable I purchased. I'm not sure how to complete the process.

My new cable is a solid piece w/ one smaller wire w/ connector. Can I combine the wires from the old cable that ran to the fuse box into one connection into the new battery cable? Please help. I'm trying to do most of the most myself but don't want to sound like an idiot. I need to learn!

Thanks, Mike