First, log into HOPS. This is the *only* machine you can access oracle from.
Once logged in, type:
cd ~oracle/signup/signmeup
And then write down the username & password it gives you. Wait 30 minutes and then you can try accessing your account by typing:
~/sql
...which after entering your login & password gives you the SQL prompt.
If you have any other problems, mail cs415@cs.jhu.edu.