Depending on what you are planning to use it for, whether personal or professional use, I would highly recommend using The Female Body Breakthrough by Rachel Cosgrove as a guide. There are some exercises in her program that I may not necessarily agree with, or prescribe to someone that I was training, however, the overall program design is good and specific for females. It also addresses (and debunks) a lot of ideas that females have about training and what they need to do to be successful, and to find results.
As a general rule, I would suggest that any beginner start with two 6 week programs. Both use circuit training.
The first 6 weeks work with light weight & high reps, this will help build muscular endurance and allow the client to work on perfecting their form at the same time.
For the second 6 weeks, work with moderate weight and reps to start building strength.
I like to incorporate stability ( single leg balance, chest press OTB, etc.) and endurance, high reps light weight for at least 4-6 weeks. A good slow progression is essential to keeping the client psychologically ready if they have been sedentary for some time as most beginners are. I really like NASM’s OPT model for beginners.
Sorry, then after the first phase I would move into strength endurance with 2-4 sets of 12-20 with supersets (one exercise immediately following another with the same biomechanical motion with minimal rest) then in the last phase or mesocycle I would bring in strength with 5-6 sets of 4-10 reps depending on the client’s progress and goals in mind.
a good beginner program for anybody addresses compenstation patterns first while strengthening the core to allow for force transference then move on to more complex training movements that involve more than one muscle at a time (complex movements vs. simple isolation movements).
There is not enough infrormation here to actually assist you in any kind of detail. Why are you looking for a 12 week program? What will this program need to do for you?
If you don’t want to post any kind of detailed information on the board then contact me through my profile and I’ll point you in the right direction.