sounds like you're not too sure about what you're doing. i'd honestly double think about installing those because it's not worth the risk.

you bust a needle, you're screwed.
if it gets extremely warm in your car, the gauge glue might come undone.
if you get sick of the look, and you will, you're stuck
your needles might not be visible anymore, all you'll see is an outline of the needle.

but ...

remove the cluster
remove the plastic shield over the speedo
use spray glue on the new gauges
slip the gauge over the needle (do not remove the needles, do not force anything)
make sure the gauges are completely flat and has needle clearance
run the wires down bottom of the cluster
attach the plastic shield back over the speedo
ground the solid color wire to the frame of the car
run the striped color wire to your fuse box
find a fuse that activates when you turn on your headlights.