Once you have the LNB off, you will see 2 ports on one side and one port by itself. You are only concerned with the two that are together. Leave the original cable plugged in and attach your jumper to the port beside it. Also leave the receiver plugged in so it will power the LNB, that $20 meter probably doesn't have enough guts to power the LNB.
Once you get everything hooked up and the LNB back in place, stand behind the dish and put your hands on opposite sides of the dish and gently 'tweak' it side to side (don't bend it!). If the signal strength rises (one direction or another), you know you can adjust it that direction. Then do the same on the top and bottom.