You should receive a cash drawer either in the box or separately. It should come in a box like the one below.
Unbox the case. It will contain 1 Cash drawer, 1 RJ11 telephone jack, 1 set of keys.
Turn the Cash drawer upside down. Connect the RJ11 Telephone jack into the receipt printer as shown below.
The cash drawer is now ready to use. Make sure to turn the key position to open, or else Cash Drawer will not open from the Point of Sale.