I no longer have EM 18.104.22.168 to check, but I believe after the Oracle Virtualization plug-in is deployed, the "Cloud" menu item shows up in the Enterprise navigation menu, and you can navigate to "Infrastructure Home" from there.
This doc may help explain a bit: Setting Up the Cloud Management Infrastructure
Loc, Thank you. Next question. The reason for wanting to do this as the upgrade guide indicates this can be used to check for any outstanding database service instance creation requests. Is there another way to perform this check or must I be able to do it form the Infrastructure Cloud Self Service Portal?
Step 2b applies to sites with DBaaS (database as a service) feature enabled. If you have not set up DBaaS, it is not necessary to check on database requests referred to in the step.
Doc on DBaaS:
By the way, it is recommended that you check out the following notes on upgrade:
1568143.1 - EM 12c R3: Checklist for Upgrading Enterprise Manager Cloud Control from Version 12.1.0.x to 22.214.171.124
1569883.1 - EM 12c R3: Checklist for Upgrading Management Agents Version 12.1.0.x to 126.96.36.199