help need with a dns server bind9 preferably

After several fails I am not even sure if a DNS server does what I used to believe that does.
I have an small network. One of the machines connected is a server (a desktop 20.04 ubuntu really). I have a private website running on that server. The problem is the users needs to enter the server ip at their browsers to see the website. I tried to install a DNS server called BIND9 on that server thinking to make things easy for visitors so they can enter a normal url instead of the server ip.
After several tries and fails doubts increased.
I follow the next tutorial in order to install BIND9

https://www.linuxbabe.com/ubuntu/set…tu-20-04-bind9

beside that did not work there is a section almost at the end
Setting Default DNS Resolver on Client Computers

What ???? do I need to configure the client computers in order to make that works ??? I can not touch the visitors computers so if I need to do something like that I am sure that will not work.

Like I said I need to change an IP address for a name to access a website. That is all. Any help is welcomed and even if you know an easier software to do that I will take that.

thanks a lot in advance and any help is welcomed
Silvano Villarroel.