VLR Rating

Can someone explain me please how this rating system works? Patti just had a game with harbour going 20 kills and 17 deaths, having 260 ACS and KAST of 80%. Despite all of this he still gets a rating of 0.9 something. I would be glad if someone is able to give an explaination clearly

i think maybe first kill first death ratio matters? but the rating system isnt good anyway

https://www.vlr.gg/160667/vlr-gg-player-rating-explained

He gave a lot of ones though, so prolly because of that