Colliding Beams | World 4 The Talos Principle Guide

Apart from the correct coupling, you also need to place the connector properly

First of all, use the connector, to redirect the blue beam from the source to the button that controls the gate. To do this properly, place the connector in the path of the red beam.

Relay the red beam towards the button in the distance

With two connectors on you, direct the red beam towards the button for the next gate (across the windows), with the third connector behind it.

Connect the beams and direct them towards the blue button

With three connectors on you, set them to point to each other, and to the blue button behind the wall - the beam needs to travel across the windows.

Cut off the red beam and make the blue beam connect there

Finally, do the same on the third connector as you did with the first button - use it to connect the second source with the connector, in the way in which you block off the red beam with the connector.