If you have an older diaper genie that does not look like the one in the link that Miranda sent you, then try this.....
1)Open the lid and remove the round collar looking thing.
2)Close the lid and pull the entire top open from the handle on the back, just below the lid hinge.
3)Take out the empty container. Open the refill and find the edge (may take a minute), pull the edge up a few inches and put the refill in it's spot. Close the top.
4)Open the lid again and pull the plastic bag up about a foot.
5)Place the collar inside the platic bag and push it down until it seets. Tie and knot in the plastic bag and push it inside the diaper genie. You are ready to go.
You can get new lid and cutting blades for the by calling 1-800-843-6430. You can also get any other replacement parts and manuals. And best of all it's free.
Good luck and congradulations on your upcoming arrival.