The following steps will help you to install IIS on Windows Server 2008 R2.
1. Open Control Panel and click on “Turn Windows Features on or off”
2. The Server Manager will appear on the screen. Click on “Add Roles”
3. The Add Role Wizard appears. Read the dialog text and click Next
4. Select Server Roles: Check Web Server (IIS) and click Next
5. Read the additional information on this screen and click Next to continue
6. Select Role Services: You can continue with the default services, or check on ASP.NET (which is optional), windows authentication and whatever else you might need. You can add anything extra you want later.
7. On this installation I selected ASP.NET and the wizard now prompts me for additional required services.
8. Click Next to continue
9. Confirm Installation Services
10. The Installation begins…
11. Complete. Now you have IIS 7 installed on your Windows 2008 R2 system.
If you need to learn how to configure IIS 7, visit the Official Microsoft IIS site