Rattling crank/hub/bearing

so i just got my new 24 inch cruiser nimbus and i realized something around the mid wheel is rattleing
not a whole lot but enough to be concerned what are some kind of trouble shooting ways to go and figure out what is rattling and how to fix it?

i think i know what it is the bolt for the cranks wasnt tightend so the washer rattled

that happened to my unicycle. at first i thought it was the spokes but the i found out it was the bolt to the cranks

if you just tighten it the rattle will go away right?

yeah mine hasnt done it since i tightened it

I thought my rattle was from spokes but it was just one of the pedals needed to be tightened.

evidentaly one the out side spacers was to small but it wont hurt it so il just let it be. i took it into rei and he looked at it which saved me from myself and tools