Hmmm...wrong section I think.
Most maps in here are BSPs, to use them just place the BSP in the mod's maps folder.(valve is for Hl1 maps)
If you don't have steam the maps folder is ...half-life/<mod name>(for example: valve)/maps
If you have steam then the maps folder is in ...steam/SteamApps/<username>/half-life/<mod name>/maps
After you placed them in the right place create a shortcut to Hl.exe and in the target range add after exerything thats written in there
-console
-dev (don't forget to add a space before each parameter). Enter Hl1 through that shortcut and in the console write
map <the name of the map>And there you go!