Choose a simple trainer design
Gather materials: foam board or balsa wood, carbon rods or wooden sticks, tape, glue, control horns, hinges, pushrods, motor, propeller, ESC, battery, receiver, servos, transmitter
Select a suitable wingspan and weight target
Draw the plane parts on the material
Cut out the fuselage, wings, tail, and control surfaces
Reinforce the wing and fuselage with spars or rods
Assemble the fuselage
Attach the wings to the fuselage
Attach the horizontal stabilizer and vertical stabilizer
Install the control surfaces with hinges
Mount the motor on the nose or pusher position
Install the ESC, receiver, and battery
Mount the servos inside the fuselage or wing
Connect servos to control surfaces with pushrods
Connect the motor to the ESC
Bind the receiver to the transmitter
Set control throws and servo directions
Balance the plane at the correct center of gravity
Secure all components firmly
Check control movement for elevator, rudder, and ailerons
Test motor rotation and propeller direction
Perform a range check on the radio system
Do a short taxi or hand-launch test
Trim the controls after the first flight
Repair and reinforce weak areas after testing