There are other, much better tutorials. However, a great deal depends on the load cell and its output. The output will change by only a few millivolts when you apply a small weight, so you need a gain of 100 or more, implying a resistance (Rg on the instrumentation amplifier) of a few hundred ohms. In order to set that accurately you will probably need to use a multiturn potentiometer in the range of about 500 ohms maximum.
Finally, if the two outputs of the load cell differ substantially, you have a voltage offset problem that is not easy to solve. If you have a good multimeter, hook up the load cell to +5 and ground (E+ and E- connections) and measure the voltages from ground to the outputs S+ and S-, with and without a test weight applied. Let us know what you find.