You should automatically be prompted to enable your mic. If you do not think your mic is on, you can click the little camera icon on the right of the address bar in Chrome or MS Edge.
There is another place to check in Chrome and MS Edge as well:
Please provide any feedback you have on this article. Your feedback will be used to improve the article and should take no more than 5 minutes to complete. Article evaluations will remain completely confidential unless you request a follow-up.