How to link to select instances exactly?

I recently set up an instance on my own server. How exactly do I select other instances to link to? And how do I select which ones to block so that I never link to them? I came across this helpful list of instances to watch out for, but how do I add or change these settings on my instance?

Just start following someone on other instance basically admin or someone else and you start getting content from there or use relays to get huge from certain instance.
There is an moderation option under that you can find fedration option use that block other instances there are different level of block you can choose from there