There are three triangle platforms on the gateway chambers that have the standard connector that you see on platforms. What are they for? Is there something specific you have to connect to them?
The connectors on gateway chambers are used for passing power. You will need to connect a specific amount of power to them and once you have provided enough and the draw has been provided for 30 seconds, the chamber will activate. You can find out more on these chambers and what they do in this guide.