You should have received an email announcing the “success” of the “one-click” installer robot, and it should contain all the further instruction you need.
Before you assume that you “messed up,” you might consider that the installer is sometimes a little “optimistic” about how quickly everything is actually “setup” and ready to rock. Particularly, if your created a new database, the subdomain for the MySQL host may not have been updated in DNS (is not yet reachable at that name) when you get the email.
If you try to enter the db host info before it is setup, you will get errors connecting to the database. This can make it look like you did something wrong, when you didn’t; you might just need to wait a bit until you can browse to your MySQL hostname.