If you dont know how to install the map then read this.

If your Half-Life folder is in the C Drive (c:/Half-Life).  Then just extract this file
directly in your C Drive.  If it is in the C:/Sierra/Half-Life.  Then just extract it into
the Sierra Folder.  If you really are confused just put the tf_dm.bsp and tf_dm.txt files
into Half-Life/tfc/maps folder and stick the tf_dmthanks.WAD into the Half-Life/valve
folder.

Enjoy the map
-TeleFragged