I just got my beats flex and the charger HOW DO I CHARGE THEM!!??

I don't know how to charge my beats flex. the cord has the same connector on each side. one side does plug into the beats but I have no idea what to plug in the other side to it does not match with anything else to plug it into it doesn't fit in to my computer or any power source please help I am pretty tech savvy and my son has beats and my husband has Bose theres plug into a normal power adaptor I'm so confused and I have looked up videos on google they don't show where to plug it in, I can't find an answer HELP ! Please !!!