First of all, from the picture, you chose a signing certificate. This certificate can be used to sign documents. After signing, if the document is tampered with, it can be detected, and its function is to prevent tampering and denial.

It is useless for you to install this certificate. All digital certificates can be installed on your computer. There are generally two purposes for installing a certificate: one is to trust the certificate, and the other is to serve as your own logo. Moreover, this signing certificate is already credible, because there is no private key, so it cannot represent itself.

This is the concept of digital certificate. If you are interested, you can learn about it.