Difference between star schema and data cube?
After spending some time, reading reference books, I came to the point, where I could define the difference between the star schema and data cubes. I could not comment on this definition but this answer satisfies me and help me to start the task. On the process, I hope I get better understanding (if exists) of these techniques. Here is my findings:

Difference between Star Schema and data cubes:


  Star schema is a dimensional modeling technique. It contains,
  Dimensions and Facts (business measurements). Mostly used in Data
  warehouse technology. 
  
  Data cube is a multi-dimensional table. It means, combination of
  dimension and fact tables. Mostly used in OLAP analysis tools. 
  
  Data cubes are built on the star schema to improve the query
  performance - performing aggregate and summarizing measurements.
  
  It will pre-calculate the values, instead of calculating on the fly,
  so it boosts performance.
  
  Example: Total item, Sales Amount, etc


Where I have to start?

I realized I have to start from, star schema and build data cubes on it. Data cubes are not built on the DBMS system, but outside the DBMS system as aggregates and other operations.

I hope this answer will help the people who are new to this technologies. If I am missing something or understanding wrongly, please correct it. Thank you.