what about sound?

Dear all, i'm a photographer and recently came across a subject i'd rather film (for a documentary): low-pofile (but nice outcome, i hope;) no huge camera's and so: need a versatile -bring it along- setup. As for camera's: i think the blackmagic pocket will do just fine..but now the big question: how do i deal with sound, what would you recomend to interview and work well with the the blackmagic? (also other useful 'gear' tips and tricks are more than welcome).. yes i'm a newbee