This image shows the bottom of the Create Compute Instance page.

In the Boot volume section there are three options. None is selected:
--Specify a Custom Boot Volume Size. Volume performance (link) varies with volume size. Default boot volume size: 256.0 GB.
--Use In-Transit Encryption. Encrypts data in transit between the instance and the boot volume.
--Encrypt This Volume with a Key That You Manage. By default, Oracle manages the keys that encrypt this volume, but you can choose a key from a vault that you have access to if you want greater control over the key's lifecycle and how it's used. Learn more about managing your own encryption keys (lini).

There is text under Login Credentials: "Upon creating this instance, both a user name and an initial password will be generated for you. They will be available on the details screen for the newly launched instance. You must create a new password upon logging into the instance for the first time." 

There is a link Show Advanced Options.
There is a Create button, which is surrounded by a red border.
There is a link for Cancel.