is there a guideline for using nix packages? - eviltoast

I want to install a package, I lookup for the package here https://search.nixos.org/packages? I can find multiple versions. two that sound right, two sound like rubbish and one is a plugin for something. How do I decide which of the two good sounding packages I should choose? What if the package or even both not work? How do I know that it is up to date? How do I know that it will be updated in a timely manner? Can I update it?