This depends what kind you got. If they're eBay ones, more than likely this is the process.
-Remove cluster from dash
-Snap off clear cluster cover
-Snap off black cluster housing
-Take new gauges and simply slide them over the old black ones.
do NOT try to remove the needles. You don't need to and you might f*ck something up.
-Take out bulbs from rear of cluster for lighting.
I ran the new gauge wires out the old bulb holes.
-Install is reverse of above.