Website development and transfer to the server

Due to the growth of the project, assistance is required in moving the site to a more powerful server. The server itself has already been rented and for ease of operation of the site and convenience we were advised to make user blogs on subdomains, and not on the main domain, as it is now. The problem is that the site first does not have such a function by default, and secondly, we have an SSL certificate for the domain, although it is for several domains (subdomains) at once, but how to organize automatic creation of subdomains and even immediately with SSL - we have no experience in this case. Control Panel on the ISP 5 server.