Improved Code Readability and Maintainability of build.sh

[PulkitBxtra]

This pull request aims to improve the code readability and maintainability of the project. It introduces several enhancements, such as variable organization, directory structure consistency, and comments for better understanding.

1. Defined directory variables to improve code readability and maintainability.
2. Used directory variables consistently throughout the script.
3. Checked if the "version.tag" file exists within the specified directory properly.
4. Added comments for clarity at various points in the script.