Also look at some people you know and who they follow. 

Yeah anyone can get a NIP05. Some people you know own a certain domain would be the only ones who can id themselves with that domain. 

Other people you might just have to do a little bit of work. 

 agree. getting your own domain makes most sense. is there a good tutorial somewhere? would love to auth with cal.com 

 It seems like cal.com is not fully translated to Portuguese.
I am available to help you with that work.
Let me know.