The usual rules for caching at Heriot Watt apply:
1. You must park at the carpark at the entrance to the grounds. The coordinates are N55 54.671 W003 18.898 (these co-ordinates are also listed as an additional waypoint below). You must have a permit to drive any further into the grounds. Alternatively you could catch a bus - the following numbers travel directly into the terminus within the campus: 25, 34, 45.
2. Although there is nothing to stop you from doing this series at night it is advised that you come during the day. The reason for this is that the campus is much better during the day, you won't be disturbing the students whilst they are overly merry and you won't cause unnecessary action for the security wondering why torches are being used in the woods.
Otherwise don't be put off of what is hopefully a nice cache in an area that likes to welcome the public.
To reach the start of the trail, head to the south west corner of the car park (by the small roundabout) and then follow the footpath north, keeping to the right hand side of the road. This will take you past GC3T277 (HW - Hermiston Walk). Cross at the zebra crossing, carry on then turn left at the forest path.
To log the cache you must simply write your name in the logbook!
Good luck and happy hunting!