Secret Chest splits up secrets (into what are commonly referred to as shards) and encrypts each with the Secure Enclave of devices. Keys derived from the Secure Enclave don't allow for decrypting these shards on other devices. Thefore, replacing an iPhone or Macbook isn't as simple as it would be with other password managers. If it were, we wouldn't be more secure than them!
People will eventually buy new devices, and the last thing anyone will want to do is recreate passkeys, reset passwords, create new SSL keys, and keygen new SSH keys. Seriously, that would suck. Therefore, we built an option to decrypt assets into what we call a partition, and move that partition to another device, like a new phone, iPad, or laptop. That might be the device that will have the secrets permanently, or it might be a device that will just have them temporarily while the new device is being setup.
If transfering directly to the new device, make sure to log into Secret Chest on the new device before doing so.
To transfer partitions, open Secret Chest and tap on the ellipse in the top right corner of the screen and click or tap Transfer Partition, as seen below.
At the Partition Transfer screen, select the device to transfer the shards and shard maps to. If there's only one other device in the account, it will be shown. If there's a new device, it could have the same name as the old device (e.g. if the transfer wizard was used to set it up). If transfering directly to a new device, use the Overwrite Main Partition Of Destination checkbox - do not do so if it's a temporary device that also has its own shards.
If using a temporary device, now go to the device that has the temporary partition and use the same process to transfer partitions to the new device once it has been setup and properly configured.