Hey Janmay,
I don't think anyone here would take the time to give you a full Facebook guide because that would take an incredible amount of time.
Here is the facebook help center https
/www.facebook.com/help/
Navigate through there, read some posts, etc and you will learn how to use facebook. Learning is mostly by doing so just create an account, dont post anything you don't want remembered 30 years later and off you go.
- LE