When the DOS screen pops up it has a directory of Z (Z:\>). You need to mount a drive where the drive location is the folder in which JNSE is stored.
As an example I have JNSE saved in C:\PCGames\JNSE. The drive letter I choose for mounting is E, as that is the first letter after C not being used by my computer. You can choose any letter you want.
Therefore the command that needs to be entered for mounting is the following - Z:\>mount e c:\pcgames\jnse (Lowercase is OK.)
After it tells you the drive is mounted, you now need to switch to the mounted drive with the following prompt - Z:\>e:
Once you have switched to the mounted drive you only have to type in the executable file (golf) for playing the game - E:\>golf
The game will then run.
The only other commands I use for the game are ALT-F12 to speed up the CPU cycles to make the screens load faster and ALT-ENTER for full screen. ALT-F11 will slow down the CPU cycles.
I hope this sort of quick and dirty tutorial helps anyone trying to play the game.