From what I've seen, there's 2 videos.
The first video shows AR guy being chased by a redshirted protester. The protester throws a Molotov cocktail at either the AR guy, or the business. The AR guy shoots him in the head.
The second video shows the AR guy running from a mob of protesters. They catch him, pushing him to the ground, whereupon he shoots three of them who were engaged with him directly. One of them attempts to pull a gun after pretending to surrender with his hands up. He is shot in response, losing a chunk of his arm.
It seems abundantly clear AR guy was acting entirely in self defense, either protecting himself or his property. No court would convict him, given the evidence in these videos. Supposedly, the shooter, 17-year-old Kyle Rittenhouse, was part of a group protecting businesses against the protesters. It's unclear if he was there protecting a specific business he had connections with, or was just there generally. However it is clear he only shot after the protesters used violent force against him, as he was running at the start of both videos, and only shot when he was directly attacked.