I see where I can export a schedule so I assume there is a place to import a schedule but I cannot find it. Can anyone help with this?

When you first create a league, there is an option on the creation screen to import a custom schedule that will be used for the first season and every year after that unless you change it. After the first season completes, then you can also change it during the "Season Start" phase of the season. The import schedule feature is in the league office screen and under the import/export menu. Once changed, the same schedule will be used until changed again using the same process.