Hi Asim,
Exercise 1 is not necessary in order to complete Exercise 6 (optimization).
As you work through the basic training exercises you can check your work against a pre-completed version of each exercise. Simply save your work, then open the LEAP area "Optimization Exercise", and select Area: Revert to Version, and choose the "complete" option. This will help guide you if you get stuck. We're happy to assist through the forums as well, but you need to provide a complete description of the problem you're seeing, what you expect to see instead, and why you expect to see that result.
Best,
Taylor