A helicopter is essentially controlled through three main control inputs.
Cyclic (control stick)
The cyclic tilts the swashplate, changing the pitch of the rotor blades depending on their position during rotation. This allows the helicopter to move forward, backward, or sideways.
Collective (collective lever)
The collective changes the pitch angle of all main rotor blades simultaneously. Increasing or decreasing this collective pitch changes the total rotor thrust, allowing the helicopter to climb or descend.
Pedals (tail rotor control)
The pedals change the pitch of the tail rotor blades. This controls the anti-torque force and allows the helicopter to rotate around its vertical axis.