electric oil pressure and volt gauge ins

I have a Autometer Electric Oil pressure and Volt Gauge that I want to install on my 2009 Colorado. I know how to install the sending unit. I don't exactly know where I should run the hot wires.I bought a couple of fuse extenders which will allow me to tap in to the fuse box. I have been told that I can tap into a ignition or a unoccupied accessory fuse terminal. I have been told yes and no concerning the use of relays. If you could walk me through the procedure that you would use, it would be much appreciated.

IGN +12V source thru a fuse (or tap into the existing meter circuit) to the +12V of the gauges, and the ground connection to the gauges. The senders to the sender input of the gauges. And light power from the park circuit if required. Simplest may be to obtain the +12V from your existing gauge cluster (before any voltage regulator if used for temp & fuel gauges). You can also get the light source from there. (Not that I know the color codes....)