Decide where you're going to mount the timer and then route the wires in behind the dropped panel so that they end by the ignition wires. I decided to mount the timer on the side of the plastic moulding to the left and slightly above where your left foot would normally be.

Connect the wiring. I used strip connectors that I had in my tool box. Other type of connectors are availble (and probably easier to use). If you're keen you could solder. I cut the wire, and bared back the insulation about 10mm. The wires from the turbo timer were twisted together with the appropriate ignition wire and poked into one end of the strip connector. The remaning end of the ignition wire was poked into strip connector and the screws firmly tightend.

The connections from the turbo timer to the ignition wiring were:
Green -> Blue/Red
White -> Black/Red
Red -> White

The observant may notice an extra strip connector in the mix. This is because I cocked up and cut the wrong wire. It is simply rejoining the cut wire.

Connect the Earth. For ease, I choose to connect the earth to a screw beneath the steering colum. I did this by crimping a connector onto the black wire and fixing it to an existing screw under the column. This photograph, taken from directly underneath looking up, shows a couple of suitable screws for earthing.

Refix the panel. Take care to keep the turbo timer wires in behind it so it all looks tidy.

Mount the timer. Obviously there are several possibilities to fix the timer to the vehicle. I would suggest not using super glue or anything else too permanent as chances are that at some point you will want access behind the panel you've mounted the timer to. I used bathroom silicon sealer that I had handy.

The nice thing about silicon is that it fixes well, but you can easily pull it off if required. It's a simple matter to peel of the dried silicon and have the panel and timer back to their orignal state. I put a block of silicon on the surface of the timer, placed the timer against the panel, and then placed a heavy block of wood against the timer to hold it in place until the silicon cured.

Further Notes:

Many timers will also have a connection to the vehicle handbrake. This is an anti theft measure. It is designed to disable the timer and cut the engine if the handbrake is released while the timer is active. My timer doesn't have this feature so I've not looked into the handbrake wiring. I would guess it shouldn't be too much drama to trace the wiring from the handbrake to connect this wire if required.

The most expenisve types of turbo timer connect to your vehicle computer. As I understand it, they monitor your driving and set the timer appropriately. Thus they require no manual setting. Most of these timers seem to come with a harness made specifically for your vehicle.