Moodle forces all items in a folder to be downloaded. It is not possible to have the files open in the same window or in a new tab. This is a security policy.
If you add the files as individual file resources to the course, rather than adding them to a folder resource, you can control whether the files opens in the browser (if possible) or is downloaded.
Ways you can contact ITS or find information:
ITS Support Portal: https://support.swarthmore.edu
Phone: x4357 (HELP) or 610-328-8513
Check out our remote resources at https://swatkb.atlassian.net/wiki/spaces/remote/overview
Check our homepage at https://swarthmore.edu/its