BEC Hookup to FW450

I have a FW450 with an APM2.6 controller board, Power Module, the kit for the 450 came with 30A Opto ESC’s and of course they have no BEC’s. Also using the Spektrum DX7s transmitter with the AR8000 RX.
So I purchased a Castle 10amp BEC and now need to hook it up. Have seen too many variations of how to hook this up and do not want to flub this up. I am using the PDB for powering the ESC’s.
Please can anyone steer me in the correct direction.
I have not seen much on the APM forum or this one yet. I am still looking.
Also using the Spektrum DX7s transmitter with the AR8000 RX.

Here in texas ready to fly.
my battery is a 5000mah 4cell lipo

What are you planning on using the BEC for if you are already powering the APM with the PM?
If you plan to use the BEC to power the APM servo output power rail, then you would plug the output of the BEC into the servo output +/- power pins and make sure that J1 is removed. This Wiki section will provide some guidance:
How do you plan to power the BEC?
TCIII Developer

That’s what the problem was. I didn’t know exactly what the BEC was for other than to control the ESC’s and I look for info but could not find any.
So the PM will take care of the ESC’s or the PDB on the 450 with the PM will work just fine.

Thanks for the info I have been a little confused as to what it’s for and why someone told me to purchase it. Guess they didn’t know I had a PM.

Thanks a lot again, now I can move forward with this build and hopefully get it off the ground.
The next challenge will be the Transmitter, receiver and tying everything together.