Refer the oracle installation manual for the script. It had been given on the oracle installation manual, and it also walks you through the set up procedure. I have seen that the script to have cause problems on 8.1.6 and Reddy or some one had posted a fix to the problem. If you serch this forum for dbstart, you would come across that fix. Rest of the stuff had been well documented on the oracle 8i installation manual and follow through that and you would fine.
Life is a journey, not a destination!