You can use a blank report as a basis to activate the sections one-by-one that will comprise it.
For this:
1 - Select the report to be customised by clicking on Assessments > Report customization > Reports
2 - Click on the button CLEAR REPORT if you want to obtain a blank report (optional)
3 - Click on + to assign a section to the report
The sections included will be shown in the Report menu on the right :
4 - Click on Publish to publish the customisation online
5 - Verify that it is indeed online in an existing report