Your project
Chat
The chat is the control. You describe the work. Build3 does it on that project and tells you what it did. You check the result in the preview.
The first message
The first prompt creates the project and starts the build. Say what it is, who it is for, and what a visitor or a player does. A specific sentence beats a vague one.
While it is working, the chat shows the steps. Wait for it to finish before you judge the preview. Sending a second, different prompt in the middle of a build makes the next step harder to follow.
Later messages
A follow-up changes the project you are in. “Make the menu easier to read on a phone” or “the jump is too short” is a complete request. Point at the part you mean.
You do not have to explain the whole site again. The project already has the current version. Say what should be different.
Chat mode
Chat mode is the switch in the composer. Turn it on when you want an answer and you do not want the project changed. A question about what to add, or how a domain works, belongs there.
Turn it off when you want the next message to build or edit. Chat mode does not publish, and it does not connect a domain. It also does not spend as much as a full build, but it is not free. The pricing page is where the amounts live.
More than one chat
You can start another chat on the same project, and you can open an older one from history. Each chat only shows its own messages. The website or game is shared. A change made in one chat is in the project the other chat will see.
Do not start a new chat to “continue” a build that is still running in the first one. Stay there until it finishes, then look at the preview.
What the chat will not do
It will not hand you a list of files to deploy somewhere else. Hosting is the publish step, and a custom name is the Domains tab.
It will not put a secret key into the page if you paste one. If it asks for a payment secret, add that in the Secrets tab and then tell the chat you saved it. Do not paste the secret into the message.