Wherever you created the superadmin.p12 key store, import this key store in your web browser or OS key ring. This is going to be your administration certificate moving forward, which you'll use to continue setting up EJBCA and can use to add other administrators.
To access the CA UI, go to https://localhost:8443/ejbca/
Before moving on, you may want to consider visiting the following guides to further improve your installation:
Recommended EJBCA Operations Pages
Some operations guides in this manual you might want to visit next: