What is the mess of wire beside it? Fix that fast before that shorts on something, or cooks up and you lose everything.
That fuse should have 2 bolts underneath the bracket holding the fuse in, one being the cable to the alternator the other one holding it to the bracket.
That fuse should have 2 bolts underneath the bracket holding the fuse in, one being the cable to the alternator the other one holding it to the bracket.