Below is a picture which outlines the different colors and their meanings.
As you can see, the yellow square indicates that a motion recording is occurring.
If you're looking to have motion trigger an event, then you should be all set.
If you'd prefer it just to be a constant recording without any motion events, then you can disable motion for the camera through Main Menu > Setup > Alarm > Motion. After this is disabled, the yellow box should turn green.
Please let us know if you have any other questions.