Diemen is a small municipality of about 30.000 residents located just outside of Amsterdam. Around a thousand years ago, people (most likely coming from Utrecht) started living around a small river called the "Diem". Hence it's current name "Diemen". People actually started settling here about two centuries before the first evidence of permament settlement in the place that's now Amsterdam.
It has multiple different public transport routes connecting it to Amsterdam and other nearby cities. Main metro- & railway stations are Diemen and Diemen-Zuid. The fastest way reach Inholland Diemen, or any of the nearby campusses, can be determined through 9292, the NS-Railplanner app or Google Maps.