Updated README.md With User Guide

[estefaniarodriguez03]

This pull request aims to enhance the README documentation for the TupiTube Desk project by adding a comprehensive user guide. The user guide covers various aspects of using TupiTube Desk for 2D animation creation and sharing. The changes include the addition of new sections, content, and a table of contents for improved readability and navigation.

Changes Made:

• Added a table of contents to provide easy access to different sections of the documentation.
• Created detailed sections covering installation, getting started, animation creation, adding audio, exporting animations, troubleshooting, and more.
• Included step-by-step instructions and explanations for each aspect of using TupiTube Desk.
• Provided clear headings and subheadings for improved organization.
• Ensured consistency in formatting and styling throughout the document.
• Corrected minor typos and grammar issues.

[xtingray]

Thank you so much for your contribution!