Oracle 11g Creating a Database (new instance)

Complete the following steps to create a database with the CREATE DATABASE statement. The examples create a database named mynewdb.

Step 1: Specify an Instance Identifier (SID)
Step 2: Ensure That the Required Environment Variables Are Set
Step 3: Choose a Database Administrator Authentication Method
Step 4: Create the Initialization Parameter File
Step 5: (Windows Only) Create an Instance
Step 6: Connect to the Instance
Step 7: Create a Server Parameter File
Step 8: Start the Instance
Step 9: Issue the CREATE DATABASE Statement
Step 10: Create Additional Tablespaces
Step 11: Run Scripts to Build Data Dictionary Views
Step 12: (Optional) Run Scripts to Install Additional Options
Step 13: Back Up the Database.
Step 14: (Optional) Enable Automatic Instance Startup

http://docs.oracle.com/cd/E11882_01/server.112/e25494/create003.htm