Hey Stuart
You might want to read thios good doc for sg300 vlans , same concept for 52 port
http://www.davemalpass.com/cisco-vlan-setup/
As well here's the admin doc its easy enough to follow too
http://www.cisco.com/c/dam/en/us/td/docs/switches/lan/csbms/sf30x_sg30x/administration_guide/78-19308-01.pdf