[quote=@ItsAnan]
[@Raineh Daze]
Canon characters elements meaning?
Their clans? Kekkei genkai? Legacies?
[/quote]
I presume they mean the base concept of the setting, the clans, how chakra works, and so forth. You could probably play around with the setting and shape the mythologies how you want since KIshimoto is a fucking idiot and has too many inconsistencies in his work. In my experience with Naruto RPs it’s best to keep in mind the heart of the series and themes you like and go from there. 

Also, a Sandbox RP is otherwise known as a character-driven story that often gives agency to the players for storytelling and a Linear RP is a narrative-driven story that often gives agency to the GM for plot direction. Both are legitimate forms. With that said I wish you luck as a fellow Naruto RPer, though between my own RP and other obligations all I can do is chime in like this – as I doubt I have the time to cohesively participate.