Enter their e-mail addresses (including the @umbc.edu domain portion) in the guest list.
Choose wheth er guests should be able to invite other guests and/or see who else is coming. When you c reate the event, Google will send your guests an e-mail asking them whether they plan to attend.
You will then see a list of your guests with blue blocks where your guests have indicated that they are busy. Remember, just because someone doesn't have anything on their calendar doesn't mean that they are available. They may not actively use Google Calendar.