https://www.opengarden.com/how-to.html
When no Internet connection or cellular networks are available, FireChat uses the radios inside our phones to connect them directly with one another. In that case (which is also called "offline" or “off-the-grid”), messages will travel up to 70 meters (210 feet) from one phone to the next.
If there are more than two devices, they will form a network and messages will bounce from one device to the next, thus extending the range of the network. The more people use FireChat, the better the network gets for everybody. This is why FireChat works really well for very large groups of people.
How will this help me?
If you are the leader of a community, give FireChat a try: it will allow you to update all community members at the same time. You can share information or discuss projects or topics in an open space for all members of your community. FireChat is well suited for live discussions. Unlike other social networks, it allows everyone to see all the messages in real time, without ads or unrelated content. Unlike messaging apps, such as WhatsApp, it accommodates a very large number of users and doesn’t require people to share their phone numbers.
How do I use it?
1. Download FireChat. The easiest way is to follow this link:*
FireChat by Open Garden. It's a small app.
2. Create your profile. Pick a username, and add a photo and a short bio. You may choose to be anonymous by picking a pseudonym, use your real name, or create the account under the name of your community or organization.
3. Start chatting. You can send private messages to people - or join a public conversation in public chatrooms. You can easily link several chatrooms by typing hashtags in any message.
4. Create your chatroom. Typing a hashtag in any message (for example #Football) automatically creates a new chatroom and starts the discussion. If the chatroom already exists, you will be joining that conversation.
5. Create a private group. To create a private group, simply send a private message to several people. FireChat does the rest.*
6. Invite your community. Tap on the “star” on the top right corner of the screen. This automatically creates a link and a screenshot of your chatroom, which you can share via Twitter, Facebook, SMS, Email. etc… You can also copy that link to use it anywhere or even type it yourself. The format is*
FireChat by Open Garden. People who follow this link will be automatically placed into your chatroom after they have downloaded FireChat. If they already have FireChat, it will simply bring them in the chatroom.
If you are “off-the-grid”, remember to keep Bluetooth and WiFi turned on so that you can see other FireChat users nearby. That’s all. You do not need to do anything else.