For installing an SSL certificate on IIS 7 a lot of information is available on the internet, since this is no different for an on premise Mendix app. Did you check this walkthrough for instance:
We did the same thing for a customer and used the following documentation of Mendix: https://docs.mendix.com/howto/on-premises-deployment/deploy-mendix-on-microsoft-windows
The problem that we still have (which does not seem to get tackled by the docs) is that all links that are published in the ws-doc/ are still using the http format instead of the https. Does anyone have an idea on how to fix this.