The Calendar is a tool where you can create and share Events and also see auto-generated events from the system.
You can switch calender view based on Month, Week and Day.
Creating Events in Calender
Creating Event Manually
To create event manually, you should first determine Calender View. If Event's start and end time will be within one day, then you should first switch to Day view.
This view will 24 hours of a day broken in various slots. You should click on slot for Event Start Time, and drag it down till you reach event end time.
Based on the selection of time slot, Start Time and End Time will be updated in the Event master. Then you can set subject for an event, and save it.
Event Based on Lead
In the Lead form, you will find a field called Next Contact By and Next Contact Date. Event will be auto created for date and person specified in this field.
Birthday Event is created based on Date of Birth specified in the Employee master.
You can set events as recurring in specific interval by Checking the "Repeat This Event".
There are two ways you can receive email reminder for an event.
Enable Reminder in Event
In the Event master, checking "Send an email reminder in the morning" will trigger notification email to all the participants for this event.
Create Email Digest
To get email reminders for event, you should set Email Digest for Calender Events.
Email Digest can be set from:
Setup > Email > Email Digest