Importing the signed certificate back into the User Key Store
Signing a certificate creates a .pem file, which is only intended for importing back into the User Key Store that contains the original certificate with the matching private key. For a server certificate this is the platform/station User Key Store that originally created the certificate and CSR. For an intermediate certificate or a code-signing certificate, this is, most likely, the Workbench User Key Store on the secure computer, which you use to sign other certificates.
You have the signed .pem files. The focus is on the User Key
Store in the appropriate stores location (Workbench or platform/station).