So many bloggers are tired of people using private blog networks for backlinks and other black hat SEO tactics outranking them in the search results. It's not much consultation to hear these bloggers will eventually get caught. In the meantime, they are earning money churning and burning. They don't care that Google will catch them because they can just get another domain and start again.
A PBN aided website can stay on the top for a while, earning its owner money. White hat SEO can take six months to show results. It's time consuming or expensive if you pay an agency to do it. It's easy to set up your own PBL; it is easier than finding guest post opportunities and then writing the post.
To set up a PBN, buy three or four domains and use private domain registration. Don't buy the domains from the same registrar and buy them on different days. Keep track of where you bought each domain and when it will expire. Get a separate cheap hosting account for each domain. The more you hide the fact that you own the blogs, the longer they will work for you.
Set up your sites with WordPress or another content management system and use different templates. The sites cannot look alike. Use SEO plugins to help the blog rank well enough to provide you with an authoritative backlink. Each blog in your network should relate to your money site. Vary them; make one or two a made up business, one a personal blog, etc. Don't link the sites to each other; only link them to your money site. Use contextual links with different anchor text.
PBN are not a white hat tactic, but there are many people making money with them. Use them at your own risk. For more information click here https://www.reddit.com/r/SEO/comments/cwg1c7/watchingasiteusingbacklinksandpbn/.