How should I place the lights?

You can place your lights as you prefer, there is not a rule!

Decorate your tree, then, thanks to the mapping procedure you can create a precise map of your LEDs and apply the effect with the maximum impact.

A useful piece of advice to obtain a good visual is to place the LEDs on the surface of the tree.

Some LEDs may be hidden from the camera, worry not, the algorithm will estimate their position, allowing a precise application of the effects.