By default, all D2L courses open to students at 12 AM on the first day of class (Summer 2016 courses therefore open May 16 at 12 AM). If you wish to give your students earlier or later access to the course, you can easily do that, as follows:

In your D2L course:

1. Go to Edit Course (top-right corner of the screen).

2. Click on Course Offering Information (the area highlighted in the screenshot I included below).

3. About halfway down the page, you’ll find the start date.

4. Make your change.

5. Click Save (bottom-left corner of the screen).