Hi Abhinav. Please do not worry. I will guide you and its damn easy to do that. Since you have already created the names that means you have created product categories. Am I correct if Yes. Then you just have to do the following below:
1. Click on Products on your admin page
2. In Products click on add new products option
3. Now enter the product description and title and then check on your right hand side. You will see an option called Set Product Image. Here is the screenshot link for the same I took for you https://tinypic.com/r/bhwy6d/9. So in this you can just enter the main picture that you want.
4. If you want to post more additional pictures of the same item then just below that option you will see another option called “Add Product Gallery images”. So you can add more multiple images for the same product under that link and all the pictures will show together for that specific product.
If your issue gets fixed let us know