Altinator is not charging battery?

Well the fusible link that I had down there was melted, so I replaced it with straight wire. It starts and runs as long as im drawing from another vehicle. The one wire down there I am concerned with is like an 18 gauge wire that I have connected a 12 gauge wire to the starter from the harness. Which wire needs the fusible link? Because I can only get a 12 gauge fusible link and its smaller than that.

Ok. Yes the altenator tested fine, so did the battery. New starter and solenoid and crank sensor and throttle sensor. I have my haynes manual but the darn thing doesnt show the wires to the starter, there are two posts on my solenoid one that is overloaded with wires and the other little post has one little purple wire. I was told it didnt matter which post the wires were on, is this true? I just put the fusible link back on, and now nothing. It wont even crank or fire now?

Also checked all voltages, all ok. Dont know what to do now. And I have been doing this for years.

Also just tried to put the fusible link on the other stud at the solenoid but it wont fit? The fusible link to the post is too small. I am trying to find a diagram for this because this isnt making any sense to me. Everything caught fire at the starter solenoid 8 months ago, I rewired it then, and she ran great until now, no symptoms, just quit starting out of nowhere. Got the schematics from gm the first time and all was good.

Thank you so much for your help. This was a wired nightmare. Nothing originally was where it was supposed to be when I first started, there was not even a ground strap on the motor. I found a hot spot in the harness from the battery to the altenator, also putting the fusible link where it was supposed to be helped. Thank you so much.