There are two options:

1) Get the DOS installation files from the Download Files section.

or

2) Create a shortcut icon to DOS on your Windows desktop.  Here's how:
    a) Right-click the mouse anywhere on the desktop.
    b) Select New -> Shortcut. 
    c) In the "Command Line" box, type "Command". 
    d) In the "Select a name" box, type the name you want for the shortcut, 
       for example, "MalbDOS". 
    e) You'll now see a new icon on your desktop.  It must now be modified 
       to work properly: 
        1. Right-click with the mouse on the icon and select "Properties".
        2. Click on the Program tab and click the [Advanced] button.
        3. Check the box for "MS-DOS mode" and click the dot for
           "Specify a new MS-DOS configuration". 
        4. In the "CONFIG.SYS for MS-DOS mode" box, change the line:
           device=C:\WINDOWS\cwbinit.exe /A
           to
           device=C:\WINDOWS\cwbinit.exe /O.
        5. Click [OK] to apply the changes and close both windows.
        6. Double-click on the icon to restart the machine in Real Mode 
           DOS for your application.  Note the settings for the Malibu, 
           in DOS, should you need to change them,  are stored in the 
           "cwbaudio.ini" file.  To find it, click Start -> Find.