You need the crypto
OAuth scope. Check if there is a way for you to use Olm for your programming language / platform. Using libsignal should be possible but has not been tested.
Use Olm to generate the device keypairs and a set of one-time keys. Decide on what the device will be called publicly (this can be changed any time). Also generate a random device ID, this can be a number or a string as long as it's securely random.
There are two device keypairs: The Curve25519 key that we call the identity key, and the Ed25519 key that we call the fingerprint key, which is used for signing and verifying that other keys belong to the same device.