Reports are set up automatically when you set up Scored Events and set up Age Groups. Setting up Scored Events create Overall Reports for each Scored Event, and setting up Age Groups create Age Group Reports for each Scored Event Age Groups are created for.
There are a default set of fields that are created for you for each Report, but you have the ability to edit each Report if you want to change what data shows.
You can edit a Report Section by going to Reports > Actions > Edit
Then you can edit the details of a Report Section using the panel for each Report Section in that Report.
To edit what columns what show in a Report Section, use the Edit Columns panel. You can remove them using the X next to the column you want to remove: