I've always found Aden's chart the easiest to use of all the one's I've seen (but as Orin said, get the lastest version 3.3). He does explain how to use it, but I'll try to give you an example for clarity.
Quote:
I don't know how to find a SC I want...
It's best to either look elsewhere or ask your party members what element the mob you're fighting is weak to. Then look on the chart for that element (in the boxes). Let's say you're fighting crabs in Qufim; you might choose Distortion (ice).
Quote:
How would I go about finding a good SC for two jobs at a certain level?
Next, you look at what weapons your DDs are using. Let's say you have a RNG (archery) and a WAR (using a Great Axe). Find the box for Distortion, and look at the listings at the start of the arrow. Under Archery, you'll find your RNG can start the SC with either Flaming Arrow or Piercing Arrow (at the Qufim level). Then look at the listings at the end of the arrow, under Great Axe, and you'll find that your WAR can use Iron Tempest to close the SC.
You will find that some jobs just can't SC well at certain levels. For instance, in the example above, you'll find that it's impossible for a MNK and a THF to make Distortion.
Hope this helped ^^