extend lve root

So the guy who setup Proxmox VE V7.4-16 on a Dell 720 has left the company and the sda3 pve-root has run out of space. I am visually challenged and a Proxmox noob ut have some Rehat / Centos and limitied Devian exposure. I've muddled my way through a number of posts on how this is done live and...