How to fix heater dial

[Hakar 1]

I had some issues with my heater, and in the Dutch forum i was told it would be my heater resistor.

I checkerd it and after trial and error i found out it should be the dial in the facia.

So i decided tot take it out.

In the dismantling proces a little ring fell down.

After a good look, it eas a little ring with two contact points on it.

 

Ireplaced it on the dial ring, and think i did it correct.

Bit, how do i fix it so it is not falling when i assembly.