Speakers and Evaluators from the agenda should be listed under Speakers/Speech Type, along with the associated time for their speeches. This is also true for contestants in a speech contest.
You can also set the standard timing for Table Topics and Evaluations, or set custom timing. The Correction control can be used to make minor adjustments, for example if you started timing a few seconds late.
In a Zoom meeting, you can share the color indicators using webcam software or a video streaming software such as OBS Studio. (Learn how)
Another technique is to share a view timer link with the audience. See blog post.
When used in the context of a contest, a Timer's Report form is displayed that you should use to report results even if you share the timer colors some other way. Contest organizers will be able to see within seconds whether anyone has been disqualified.
Contestants will be listed under Speakers/Speech Type, according to the official speaking order. When you click Stop on the timer, the speaker's time will be added to the Timer's Report form, with the Disqualified checkbox check for times over or under by more than 30 seconds. You can make adjustments as necessary.