Comodo (CA) will email you a zip file containing the following :
Intermediate CA certificate
The file must be in PKCS #7 format in order to be imported into a Server Certificate object. The file must contain all of the certificates to be imported into the object (the root-level CA Certificate, the intermediate CA certificates, and the server certificate).
To view the subject, double click the certificate that Comodo (CA) sent you, then click on the detail tab and go to the subject area.
To successfully install the Certificates:
Import both the "Intermediate CA certificate" and " Root certificate" into Internet Explorer. Do this by double clicking on each of the certificates and choosing import. Make sure they are imported into the correct stores: "Intermediate CA certificate" goes into the intermediate store and " Root certificate" goes into the root store.
Double click the certificate that was signed by Comodo (your server/domain certificate) and go to the details tab, then click on Copy to File. Next, Select "Cryptographic Message Syntax Standard - PKCS #7 Certificates (.P7B)" and select the "Include all certificates in the certification path if possible" check box. Name the file (for example "c:\mycert"). This step will put the Trusted Root, Intermediate Root, and End Server certificates into one certificate.
Go to Console One and to the certificate that created the Certificate Signing Request (CSR). Go to the Public Key Certificate Tab. Select Import, select "No Trusted Root Certificate available", then next. Import the Server Certificate that you created above.
After the import, you should be able to validate the certificate and use the certificate.
The certificate is now ready to use.