It doesn't matter what you're making. A DataGridView is a DataGridView and it works the same way regardless of what the data it contains means to the user. Learn how to use a DataGridView and then use that knowledge to make it do what you want it to. There is no magic property of the DataGridView that makes it work as a calendar. It's what you do with the data that gives it meaning.
I've shown you how to find the information you need to answer the question you asked. Read it, use it, test it, understand it and then, if you have other specific questions about other aspects of your app, start a new thread on a new topic.