Since Access itself doesn't actually HAVE an internal calendar format, the problem is to define where you would store the downloaded information. Outlook DOES have an internal calendar and Access (using an Outlook Application Object) can interact with it on your local machine or in any other .PST file to which you have permissions to read/write.
Access keeps dates as isolated data elements. If you build a calendar in Access, internally it would just be some sort of recordset (in tables). You would define your own structure for such a thing.
It is your app, so I won't choose a way for you. But your choices are either to use Outlook calendars as a repository or to build some data layout in a table to make your own calendar. Either way will have its complexities.
IF you choose Outlook, you will need to research how Access deals with Application Objects and in particular, Outlook objects.
If you "roll your own" then you have to design a method of data layout that will give you the level of interaction that you need for your purposes.