r/canitrundoom

I know It can, but I don't understand how can I download it. I heard that doom is free and open source but I can't find where and how download it. I found freedom but wtf is that, it's not doom. I spent like hour trying to understand how to fucking download doom. please help. how people just run doom on everything when I can't get it running on machine that sure can run it. am I too stupid pls help