The university of Warwick is located in Coventry, NOT in the town called Warwick!
The University of Warwick has an excellent guide on how to reach campus here.
In short, the closest train station is Coventry with frequent direct connections to London Euston, Manchester and Scotland via Birmingham and the Midlands, and Dorset via Oxford, Reading and Southampton. On the platform, head for the more modern of the two overpasses and exit onto the road bridge crossing the railway. Turn left to reach a bus stop with frequent departures by line 12X to campus. Disembark the bus at the University Interchange.
From the University Interchange bus stop, the Zeeman Building is a 10-minute walk away. The main entrance is here: Google Maps link, What 3 Words location:park.slurs.translated