SAN FRANCISCO — Google is launching a live video chat service that connects people with personal trainers, contractors, music teachers and other experts who can teach them how to do stuff.

Envision Hangouts with an expert on the other end — say, a yoga teacher or a math tutor. The idea is to get a helping hand when you need one.

The new service, which has been rumored for months, initially will be staffed by experts vetted by Google. Health care professionals will have to be licensed.

“Google’s mission is to organize all the world’s useful information,” Udi Manber, a Google vice president of engineering, said during a news briefing in San Francisco Monday. “I have been doing search for a long time, and most of the world’s useful information still resides in people’s heads. This opens the door to that information.”

Google said it’s starting small and in only a few categories. Helpouts joins a plethora of how-to services on the Web, including message boards, YouTube videos and question-and-answer websites, such as Quora. Amazon debuted a one-on-one video help feature in September.

Consumers must have a Google Plus account to participate. Then they can review the experts’ qualifications, price, ratings and reviews, and then book appointments or get advice on the fly.

During a Helpout, you can share your computer screen or record the session.

The Helpouts experts decide how much they charge, either a flat rate or by the minute, and Google handles payment via Google Wallet and takes a 20 percent cut. If consumers are not happy with the service they receive, they get their money back, Google said.