For creating a configurable product you should follow the next steps:
1. Log in to your Magento admin panel
2. Select the "Catalog" tab
3. Click "Manage Products"
4. And then click the "Add Product" button to add a new product
5. Select the attribute set and the product type
Note: Configurable products could be created only for certain attributes. Make sure that your attribute fits these requirements.
6. Type the product information
7. Once you’ve entered the "Associated Products" page, click the "Save And Continue Edit" button
8. You can see the area where you can create simple products with the same information as the configurable product but with different values of the chosen attribute.
9. Here you can create the products with different attribute values. Make sure that these products are not visible.
10. Set the price for each attribute value. Note that you can select 2 types of prices. Fixed value that is added to the product price or percentage of the initial product price.
11. Save the product
12. No you can return to your front-end and check the configurable product.
For more details please check the video tutorial belowMagento. How to create a configurable product,