1. Select the location of your windows Server 2008 R2 installer DVD. Once the selected windows Server 2008 R2 is loaded you will get the list of images as below

2. Now enable "Slipstream service pack" option and select the image you want to slipstream service pack and click OK button as below

3. A new window will be opened as below in the screenshot. Select a valid service pack file and click the start button. If you want to skip the service pack integration then simply click the SKIP button.

4. RT Server Customizer will now start the integration.

5. RT Server Customizer will finally save the progress and completes it.

6. Once its completed you can either proceed further to start customizing with service pack integrated or simply exit the application after service pack is integrated.