Logging on to OSgrid
First, set up an account on the OSgrid.
There are other viewers that are as straightforward to use with OSgrid and other Hypergrid projects: for example, Imprudence viewer.
It is possible to use the standard Second Life viewer, but this is less straightforward. Instructions are on the OSgrid site.
Viewers are available for Macs running OS X, Windows PCs and Linux machines.