[ISSUE #17] Improve the tutorials section in docs

[Whitegabriella789]

The two example tutorials have been revised through Jupyter Notebooks, and the tutorial doc is more in-depth, per your request. I apologize again for any confusion, and thank you for your patience as I'm still learning how to collaborate on GitHub. If there's anything that needs fixing, do let me know, and I'll be glad to look at it again.

fixed #17