Above All That (yellow)
You will need a new item for this level - the Connector. To unlock this device you must get all the yellow sigils required. Then you must solve the riddle with the sigils. More in the chapter with all the sigil riddles solutions. Use the new item in the way shown on the picture.
Set the sockets so that the door opens. You must secure the continuity of the laser beam for the device to fully work. Then take the sigil behind the door.
Branch it Out (yellow)
In this level you must use all the sockets in the way shown on the picture. You must open two doors simultaneously, only then the road to the sigil will be open.
Don't Cross the Streams! (yellow)
In this level you have sockets in two different colors, to open the doors their beans can't intersect and they must connect with the right receiver near the door. Move away with the blue beam behind the building standing in the center and use the red beam inside the blue one, as shown on the picture.
Push it Further (yellow)
You must set the blue beam so that it will be on higher level than the red one, then they won't intersect and the doors will be open.