Need help on setting up database star schema and the queries

Starting from the database used in Project 1 (see the slightly changed schema from the original version used in P1, defined in the attached DDL file), a data warehouse star schema with the following characteristics will be defined: 

• Dimension tables: 
1. Date 
2. Product 
3. Customer
• Fact table: 
1. Sales 

For this final project, perform the following steps: 

• Create the tables defined above in a star schema. Add the necessary columns in each table to facilitate the implementation of the queries defined below. Only the four tables listed above are allowed in that star schema 
• Write PL/SQL code (anonymous blocks and/or subprograms) to populate the warehouse schema with data from the normalized database provided in the attached DDL script 
• Write SQL code to perform the following queries: 
1. What customer age group spent the most money in the last year? An age group is defined as a ten years interval, such as: 11 – 20, 21 – 30, etc 
2. In what zip codes did the highest number of sales (number of items) occur during April 2015? 
3. What day of the week did they do most business (by value of sales) in the last year? 
4. What quarter is the worst (by value of sales) for each product category, using the whole set of historical data available in the warehouse? 
5. What was the best sales month for each product in the last year?