You can check the upcoming events from this Events Umbrella's home page.

You can go to the event's site by clicking on More info.

Event site is open depends on event's permission level. You can join to a group by clicking on the Join Now button on the Event home page.

If the event has open membership, you join automatically when you click Join This Group. The group page shows the change in membership status.

If the event requires approval to join, Event Umbrella  notifies the group owners of your membership request. You are notified by email of your acceptance or rejection.