Upon move-in, you are given a small wallet for your residence access key card (to get in the building) and a laundry card. The laundry card will have a serial number on it. I don't remember the website but it should be in your move-in residence manual or you can just ask anyone at the Commons building desk. One option to reload it is online by registering your card to your email and then using a credit card to reload it. Another option is to use the machines that accept cash (I'm pretty sure it doesn't take coins). There's one in Keyes lobby and one in the Commons building across from the service desk. You insert your card, insert your cash, done.
Yes, you have to bring your own detergent, dryer sheets, and laundry basket. It costs $1.50 for one wash cycle and $1.50 for a drying cycle so a total of $3.00 each time you do laundry. You insert your card before each wash/dry cycle and select all your options. When the machine starts up you can remove your card. It's pretty simple.
says thanks to Imperious for this post.