alternator

I bought a new alternator for my 1989 Chevrolet 4x4 1500 pickup. my battery light comes on and sometimes it flashes. when I drive it looses speed and want go over 30 to 40 mph. I was wanting to know also the wiring of the alternator I know the alternator charges the battery but where all does it feed before it gets to the battery? I already ask this question before but I had to get another email accont because it kept telling me I was a invalid user .