Sell the car, buy a bicycle.
But yeah, what Newman said. Alternator isn’t turning because the belt is super loose. Fix the adjuster mechanism, put on a new belt since the old one is probably worn to shit from being so loose, tighten it, and go from there.
Don’t drive it at all, because you’re probably not turning your water pump either.
When you’re done, jack the car up, put your head under the front tire, and release the jack.