Rig made with Rigify doesnt moves mesh

I want to create a videogame. I have little experience with Blender, but I wanted to learn it anyway, so I started my project with this. I am trying to make one of the enemy character, but I have ran into a problem: i made the armature and the rig using rigify, but the rig simply doesnt wants to move the mesh for some reason. I already watched like 6 tutorials, read 4 posts, and tried to figure it out for 8 hours straight - without finding a solution.
I would really much appreciate if somebody could help me.

Here is the file: https://drive.google.com/file/d/1OBUCYLEpnGJ30GGlGZ-0ZRdEslt1hnzu/view?usp=sharing

I downloaded the model i am using as my mesh from the internet, so I hope the problem isnt the mesh itself.

Well you have parented the armature to the mesh as an object. That won’t work. Plus your mesh is not ready for Blender. Here is a little video I made for you. Hope it helps. Pardon the bad audio, my mike messed up.

Welcome to the forum!