If you're driving, this is the view from 21st Ave.  You'll need to turn left on the road you see in the picture (Terrace Place) -- ISIS will be on your right:

You can park in the garage across the street, spaces 41-92.  Ring the ISIS doorbell (the front door is locked), and the secretary will let you in.  Tell her you are with SIPHER, and she'll get you a parking permit and tell you where to go.

If you're walking to ISIS from campus, then when you reach 21st Ave. from campus, you'll see a view like this:

Keep walking straight, ISIS is the building on the right.