The object is to get a closed loop for each colored light. This is done, at the early levels, by rotating individual pieces. Look at the second image. To get the blue light you'll have to rotate the corner piece, the pipe above it and the terminus.
The 4th image shows gears - meaning that you if you rotate one, they all rotate. Think about this: what if you want just some of them to rotate, not all?
The 'mirror' tile (not shown in any of these images) will reflect the image of a neighboring tile.
There are 100 levels of Light Weaving.
I stopped at level 73. And just for good measure, and some fun, completed all 100 in the last couple of days. Surprisingly, the last 10 are kind of easy.
There's a lot of fiddling with this game. To get 3 stars - you must concentrate.
We've seen this type of puzzle before - but just at the basic levels. Dapeng has really made some great innovations here.