Hello Krish,
if this is the root certificate, which is used to sign the user certificates,
it should be enough.
If you import the root cert in the strust, you tell the SAP system to trust user certificates, which are signed by this root cert.
The mapping must be done in transaction certrule.
The user certificate must contain the username in the DN. This must be the same name as the user has in SAP.
Does this answer you question?
Regards
Manuel