• Click the Start Button then selct Run and type mmc
• Click File and select Add/Remove Snap in
• Select Add, select Certificates from the Add Standalone Snap-in box and click Add
• Select Computer Account and click Finish
• Close the Add Standalone Snap-in box, click OK in the Add/Remove Snap in
  Return to the MMC
  
• To install the GTECyberTrustRoot Certificate:

• Right click the Trusted Root Certification Authorities, select All Tasks, select Import.

• Click Next.

• Locate the GTECyberTrustRoot Certificate and click Next.
• When the wizard is completed, click Finish.
  
• To install the ComodoSecurityServicesCA Certificate:

• Right click the Intermediate Certification Authorities, select All Tasks, select Import.
• Complete the import wizard again, but this time locating the ComodoSecurityServicesCA Certificate when prompted for the Certificate file.
  
• Ensure that the GTECyberTrustRoot certificate appears under Trusted Root Certification Authorities
• Ensure that the ComodoSecurityServicesCA appears under Intermediate Certification Authorities

Installing your IIS SSL Certificate:

• Select Administrative Tools
• Start Internet Services Manager

• Open the properties window for the website. You can do this by right clicking on the Default Website and selecting Properties from the menu.
• Open Directory Security by right clicking on the Directory Security tab

• Click Server Certificate. The following Wizard will appear:

• Choose to Process the Pending Request and Install the Certificate. Click Next.
• Enter the location of your IIS SSL certificate (you may also browse to locate your IIS SSL certificate), and then click Next.
• Read the summary screen to be sure that you are processing the correct certificate, and then click Next.
• You will see a confirmation screen. When you have read this information, click Next.
• You now have an IIS SSL server certificate installed.