Altenator help

My battery died two days ago. I bought a new battery yesterday because the old one was well past its warranty and I just assumed it was dead. New battery isn’t charging. I start checking stuff out and the positive cable that runs from the battery to the alternator has pulled out. No connector, just some copper sticking out of the red rubber. How do I go about fixing it the easiest way? It’s a 98 Isuzu Hombre 2.2l. Same as an s10 or Sonoma