Cannot get small handheld to work alone？

Kindly double confirm if installed correctly or not. The switch knob should always be on the left side. The hex nut(labeled with a yellow code) should connect to the water outlet.

It is leaking water from the connection between the 3-way diverter and the water supply pipe.

1. Check if the black washer is seated well in the 3-way diverter. Or replace it with the extra new washer.

2. Remove the old pipe tapes and wrap 4-5 times new teflon tapes around the pipe threads.

3. Tighten the connection clockwise with a wrench.

The showerhead tends to shake left and right in the connection.

Connect the hex nut to shower arm by hand clockwise until it cannot be moved, then tighten it with a wrench.

Is the main head can adjust the angles?

Yes, it can be adjusted the angles to fix your needs with the swivel ball joint.