I wouldn't trust his guides personally. He has some hot takes and more importantly he isn't someone who really knows the Homelab/self hosting landscape.

If you are looking for guides I would find channels that have done series on whatever you are interested in there is plenty of quality material.

To start off here is what I would do.

First, get a wireless router that is capable of running OpenWRT and then get a switch to accompany it.

Next go to eBay and buy 3 used workstations. They don't need to be fancy and you can always upgrade them later. You need 3 for later.

Next find some storage. You can find decent Sata SSDs for pretty cheap. If you are looking to store something bigger like a movie collection also pickup some larger drives. With the extra drives make sure you buy a sata or SAS pcie card. This is because you need a dedicated controller to passthough to a VM.

Once you have all that you can start installing Proxmox. You probably want a raid 1 configuration so that you can replace a disk without downtime. The reason I say three devices is because you need 3 machines to get consensus in the cluster. When consensus is lost affected devices go into what is called fencing which is where it freezes all VMs and operations to prevent split brain from happening.

Technically this is probably a bit overkill but I like having a solid base for experimentation and flexibility. Doing it right from the get go will mean that you have more power down the road.

For actually hosting stuff I would use docker compose inside a VM.