To restrict user access to certain reports:

1. Go to 'Security' -> 'User Administration'.

2. Select the user and click the '+' sign to expand their record.

3. Navigate to the 'Restrict User Reports' tab.

4. Click 'New Record' and choose the specific report to restrict by selecting its Reporting Area, Reporting Group, and Report Number.

5. Click the save icon and repeat for each report you want to restrict.