Secrets are created in the Secret Chest app on an iPhone, an iPad, or a Mac. First, open Secret Chest.
At the main Secret Chest screen, click or tap on Add Secret, or See All. The See All button opens a list of all of the secrets on a device. That too has an Add Secret button.
At the secret screen, enter a domain, username, and password. Also use the checkboxes to define which devices will receive a shard, or part, of the secret being created.
Click or tap on the INSTALL button. An installation map will then be created and Secret Chest will attempt to create shards on each device selected. If a device has Secret Chest open, the process happens automatically. If a device does not have Secret Chest open, a push notification will then be sent to any members of the secret society of awesome devices that don't yet have its shard. Once opened those are created automatically. It's worth noting that accessing the Secure Enclave to create a secret does not require a Touch ID or Face ID. However, to access the objects later will require it.
Secrets can also be created in the auto-fill screen when selecting to fill a password with Secret Chest set to the appropriate extension to use for that entry. Once created, the next step is to try to retrieve or change the secret and make sure it's all good, a process laid out in this article: https://www.secret-chest.com/post/retrieve-and-update-a-secret-in-secret-chest.