"techgirl" has provided solid advice.....

1. AA operates domestic service from terminals A&C, with mixed domestic & international flights ARR/DPT in the new "D". American Eagle, RJs and Saab turboprops, unlikely for a SAT flight, are in B.

2. There are two "Skytrain" staions in each terminal (all with trains in both directions every couple of minutes), reducing walks to no more than 1 100 yeards in almost every case. The entire loop is quick, with no more than 15 minutes for the circuit.

3. An AA FA will anoounce, likely while taxiing in from the boondocks of DFW, the terminal and gate # of your arrival, and the departure terminal and gate # of your SAT departure.

4. "The Back of the Book", in AA's inflight mag has the same diagram which is repeated throughout the terminals (and occasional banks of video will allow you to confirm the gate announcement), allowing you to locate the nearest "station", head up the escalator and travel to the station nearest your departure gate, then turn right of left to stumble upon it.

"Piece of cake" as the expression goes, and DFW may be the easiest large US airport in which to get around.