Once you install the tool just select all the contacts who you want to receive the alert in case of an emergency from your contacts book. The best part of Trusted Contacts is that, because it's a Google tool, it's easy to select the desired contacts from any of the accounts linked to your device. Once you've selected your friends and family, you can start to use the app.
In case of an emergency, or if you have some other reason to share your whereabouts, just tap the button to send your location. You'll have two options: send your location to a new selection of contacts or send it straight to the contacts selected when you installed the app. Once you tap this button, everyone will receive a message with your exact location on a map. From there, they can send you a request for a response, to which you can then reply reassuring them that everything's okay. If you don't reply, your contacts can call for emergency services. Keep yourself safe by getting Trusted Contacts just in case something happens to you.