Hello, I did a engine swap and completed it a few days ago, i then attempted, to connect the battery and instantly had insane sparks on positive and my fusible link started smoking and got really hot, after that only my high beam works, no accessories on dash no dome lights no cranks, pure dead. My ground is on the fire wall, i have a ground on behind the engine going down to the starter, and my fuse box has a ground,

I then took a look at my alternator and saw there was not a rubber behind the positive bolt and saw a random ground not connected to the alternator, where should i begin with this? My battery is new

i apologize if I'm not being to specific , I'm fairly new to this kind of work so im still learning