install instructions if you are a player (not a server), and you have counter-strike (you don't need to download anything)
1. copy cs_dust.wad from half-life/cstrike to half-life/ns
2. copy de_dust.bsp from from half-life/cstrike/maps to half-life/ns/maps
and you can play (if you want the minimap, follow the next instructions)
install instructions for servers or players that don't have counter-strike
1. download de_dust-for-ns.zip
2. put de_dust.bsp in half-life/ns/maps
3. put cs_dust.wad in half-life/ns
4. put de_dust.spr in half-life/ns/sprites/minimaps
the entity file (de_dust.ent) is also included in the zip in case you want to edit anything or see how it was done
you will need ripent to use it
to join a team, hit F4 and don't move - you will be assigned to a team automatically