Setting up MSDOS 7.1 and make a boot dist.

In 1984, I wrote a water treatment program that will take the water components (TDS, Chlorides, P and M alkalinity, pH, etc.) from cooling water, boiler, chiller water or incoming make-up water and produce the cycles of concentration up to 20 levels and the most importantly the Ryznar Stability Index. I have downloaded the MSDOS 7.1 from SysChat but there are no directions as to how one would produce the boot disk. With the boot disk, I can type in my program for the first time since 1984 and use the program to help a friend in need. Can anyone help me?