Case - 1 : If you have a p7b certificate:
1. Double click on the cert and you should see the p7b cert opening in MMC console. In the MMC console, expand the certificate path and click on certificates in the left pane. Once done, you should see the certs in there.
2. From the list, double click on the certificate that has the URL in it and click on Details tab.
3. Select Copy to File.
4. In the Certificate Export Wizard, click Next.
5. Select Base-64 encoded X.509 (.CER) and click Next.
6. Click Browse to enter a name for your exported certificate save it in a specific directory with the name as 'domain'. Click Save then click Next >.
7. Click Finish to export your certificate to the desired directory. Click OK after the export completes.
8. Now, go to the location where you have saved the certificate, and double click on the certificate. Once the cert is open, click on Certification Path tab and double click on the certificate present one level above the highlighted certificate.
9. In the new certificate that is open, click on Details tab and follow the same procedure again to extract the next certificate.
Similarly, depending on the number of certificates, you will have to repeat the process till you have exacted all the certificates.