Step 1. Open get started with orcale from your desktop:
Browser will be opened .Let it load.
Step 2. Open application express
Step 3. Database username and passward:
Now Use SYSTEM as usernameand Password : 123
Step 4.
Now create new database as following:database username: testingdb
application express username: testingdb
passward: 123
then click on create workspace. Done. Now you can exit browser.
Step 5.
Go to sql developer. Click on symbol to Create new connection.enter following details as in image with. password is again 123
click on connect and then type the query.Cogratulations you made it.
note: if it doesnt work restart the application or restart the computer.