the TO 1-1B-40 is a general USAF technical order related to weight and balance of aircrafts. There you will find some general procedures and definitions.
In any case, you must refer to the specific W&B manual of your aircraft for detailed information about how is computed the basic weight and where it is measured, there you should find what are the weight and CG limits you must respect to ensure the stability and controllability of you’re A/C
Nicolas