how do i charge my 3 channel syma s018 mini airwolf rc helicopter?

i got a r.c. helicopter a couple of years ago and then it broke. It lasted for a year and i figured out just about every thing i needed to know so i trashed the operation manual. after that the tail broke off and i stored it. a couple of days ago i decided to get it fixed and i cant remember how to charge it. any one remember how?

I think you use a USB cable. And connect it to a computer. And charge