Gavin, you can look here for various ACI design guides, and best practice/White papers.https://www.cisco.com/c/en/us/solutions/data-center-virtualization/application-centric-infrastructure/white-paper-listing.html

You be able to access the APIC via the APIC CIMC - and continue so after the APIC is configured and all components in the fabric are discovered. Once the fabric discovery is complete, however you should be able to access the APIC via 'ssh' as 'admin'...