You can create events for all your commitments, be it a team meeting or a personal appointment. Events are available at the network level, the group level, and at the user level. Creating events at the network level and the group level depends on the permissions set by the admins.
All Events
This shows you all events that you've created or invited to. This includes Private Events, Company Events, all events from groups you belong to, and events from other groups that you are invited to.
Private Events
When you create a private event, it is visible only to you and your invitees. Checking the private events option in the left pane shows you private events you've created and the ones you've been invited to.
Shared with me
Checking this option in the left shows events you are invited to from groups you don't belong.
Company Events
These are events created at the network level. They get posted on the network wall, and all members in your network can view it. Checking this option on the left will show you all the network events.
Group Events
Use the check boxes next to the listed Groups in the left menu to show or hide events in them. Once an event is created in a group, it gets posted on the group wall, and all members can view it.