I researched this a while back when I was planning on doing the same (but never got round to it). I've just checked the Paintworks Studio website and it's been updated since I last looked. It is a fairly simple "12 minute" walk from the station. I doubt you could easily get lost...
Look here for more info -
http://www.paintworksbristol.co.uk/file ... cation.pdf
By Rail
From Temple Meads Railway Station, head left along the A4 towards Bath then bear left at Three Lamps junction. Continue for approx half a mile, Paintworks is on the left hand side. It’s about a 12 minute walk.
Buses
Paintworks is served by a number of buses running from the centre of Bristol harbour area and from Temple Meads station: 1, 57 & 349.