I will assume you are talking about WebUtil 11 in Forms 11.x. If true, most of the configuration is completed by the product installation. There are some minor steps required and those details can be found in MyOracleSupport note ID 1093985.1
In order to complete the steps correctly, you will need to know exactly which Forms version you are using. For example, 188.8.131.52, 184.108.40.206, etc
If you don't have access to My Oracle Support, then search the Oracle Forms Help system for: Configure Webutil. This will return three results: Configuring WebUtil, Introduction to WebUtil and Runtime Setup Checlist. I recommend you print the Configuring WebUtil and Runtime Setup Checklist and complete each step in the checklist.