On my LCD I have already wired it up for parallel connection, so the contrast adjustment is on the screen. If your LCD is not hooked up to anything, this potentiometer is here to adjust the contrast. I have no completely wired it as I have no use for it as of yet, but here is how it goes together. The slider pin should be connected to the wire that will go to pin 3 of the LCD. The other two ends should be connected to 5V+ and Ground. OH yeah, the potentiometer is 10k. The only reason I used a slide potentiometer is because I liked it. You can use a rotational one. Lastly, the R/W connection will be connected to ground, so ad a jumper wire from the ground rail for the pin 5 R/W line on the LCD.