I have circuit diagram but i don't know how to operating principle. Please explain to me. Thank you so much!

 

It's a block diagram of an RF amplifier. It combines the outputs of four power amps into one output.

 

That shows block diagrams, the inputted RF is divided into four signals feeding four separate pairs of Mosfet RF amplifiers and then summed their eight outputs to yield higher power level signal.
Some protection circuits for overcurrent, SWR and temperature control the SCR in three phases of the mains to protect the amplifiers.
Miguel