In large corporations, everyone's schedule is packed with meetings. This makes is difficult to schedule the important meetings Scrum needs.
I have created a template that I have been using that is simple and easy.
It includes the name of the project and the sprints contained in a given release. Dates of important activities and meetings are also included.
Once the dates have been established, I schedule All Of The Meetings well in advance. Normally schedules are more open weeks in advance. Once these meetings are on the team's calendar, they schedule other meetings around the existing sprint meetings.
You may access a copy of the template here.