Should I know who Kazuki and Shiharu are?

they are in a lot of Fujisaki Kou's stories.

if you don't already, then it's way past time to get introduced lol they are def one of my favorite power couples!
this is the first manga in the series.. be aware that the main characters in this one are not chicaru or kazuki but they get introcuced in this one.. it's a good series.
http://www.mangago.zone/read-manga/happy_yarou_wedding/

I see, thank you for clarifying, I thought it was some kind of Dj about a pop group or something like that. (￣∇￣")