This should be the last thing you connect. The drain outlet will be connected to the dishwasher, so it's a matter of feeding this pipe through to the underneath of the kitchen sink. The drain piping might not already be connected, in this case, locate the drainage hole in the back of the dishwasher, and connect the piping.
The dishwasher should come on some runners, which help when maneuvering the dishwasher about. As you slide the dishwasher into it's final position, feed the drain outlet piping through to the sink. Generally the piping won't be long enough to reach all the way to the sink when the dishwasher is out of position, so you will probably need to feed the piping through bit by bit as you slide the dishwasher in.
Feeding the piping through might not be as easy as it sounds. If this is your first dishwasher, you will likely need to drill or saw a hole for the drainage pipe into your kitchen units. You can do this before the dishwasher arrives to save time later. Getting a saw round the back of your kitchen units may be awkward, so an electric drill is recommended. Use a large drill bit to drill holes outlining where your pipe will go. Once the outline is complete, the centre part of the hole will fall out.
The drainage pipe can then be connected to the rest of the piping underneath the sink:
You may need to install the side fitting under the sink. Otherwise, connect up the drainage pipe as in the picture above. It's important that the connection is high enough up, and not part or the U bend at the bottom, or your dishwasher may get clogged with waste from the sink.
In some cases, attaching this fitting may not be an option. When this situation arises, a dedicated waste pipe will be used./p>