How to grant view permissions to reports in SSRS 2008 R2

Hi,

I am able to generate rdl files from report server wizard and upload them and view them. I uploaded them in a folder. I gave system user permissions to a couple of users at site settings link on reports manager and at the folder level I gave them browser only. However the users are able to manage the content of the folder as well as reports. How can I prevent this? Do you think I need to create a specific role on ReportServer database and add these users to that role?

Thanks for your help in advance.