By your comment I believe you are looking for NTFS permission and not the Reporting Services permissions. Try this:
- 'Run as' administrator IE and open your http://localhost/Reports (or whatever is the URL)
- In the top right corner click on 'Site Setting' (http://localhost/Reports/Pages/Settings.aspx)
- Check the 'Security' settings (http://localhost/Reports/Pages/Settings.aspx?SelectedSubTabId=SecurityLinkID)
- After you set the permissions how you need, relaunch the browser without with your normal account and try it.
For more information about how to set the permissions read here: https://msdn.microsoft.com/en-us/library/ms156034(v=sql.110).aspx
To add a user or group to a system role
- Start Report Manager (SSRS).
- Click Site Settings.
- Click Security.
- Click New Role Assignment.
- In Group or user name, enter a Windows domain user or group account
in this format: \. If you are using forms
authentication or custom security, specify the user or group account
in the format that is correct for your deployment.
- Select a system role, and then click OK. [Roles are cumulative, so if you select both System Administrator and System User, a user or
group will be able to perform the tasks in both roles.]
- Repeat to create assignments for additional users or groups.
To add a user or group to an item role
- Start Report Manager and locate the report item for which you want
to add a user or group.
- Hover over the item, and click the drop-down arrow.
- In the drop-down menu, click Security.
- Click New Role Assignment.
Note If an item currently inherits security from a parent item, click Edit Item Security in the toolbar to change the security settings.
Then click New Role Assignment.
- In Group or user name, enter a Windows domain user or group account
in this format: \. If you are using forms
authentication or custom security, specify the user or group account
in the format that is correct for your deployment.
- Select one or more role definitions that describe how the user or
group should access the item, and then click OK.
- Repeat to create assignments for additional users or groups.