Just posted this for a beginner in electrics. i found it useful information for myself
When ESC HAS NOT built-in BEC function
No change is needed for ESC, just connect the input cables of UBEC with the battery, and plug the UBEC’s output cable (connector) into one spare channel of receiver.
When ESC HAS built-in BEC function
You must disable the BEC function of ESC, i.e. you must first cut the red wire in the trio of receiver wires. Simply use a pair of wire cutters to remove a short section of the red wire near the receiver connector, and insulate the cut wire with a bit of electrical tape.
or it can be removed from the connecter with a sharp screw driver and insulated