Https for react app behind domain

Hi,

I am currently trying to set up the following:

React app A in a docker Container, hosted in Server S with a static IP address

Domain D with subdomain Ds, not in any form connected to Server S.

A certificate C exists for D that includes Ds.

Requests for the app A will be sent to Ds and forwarded to A.

How would I have to change the existing certificate C or set up a new certificate to be able to use https for the requests?

Would I have to provide the certificates to anything beyond app A?