server configuration or htaccess for many domains serving one web-project (root access to server)

I have lots of domains pointing to one server (ubuntu 18.04 LTS). All domains point to the same directory (/var/www/vhosts/[login to view URL]) Only the major domain ([login to view URL]) has got an SSL-certificate. 1.) If called by http is must be redirected to https. 2.) It shall call then [login to view URL] (like usually with parameters) The other domains ([login to view URL], [login to view URL], ...) do NOT have SSL-certificate, so we have to downgrade if called with https: to http. ... and for these domains (all not equal to [login to view URL]) we call a different php by default. 1.) If any of these domains is called with https:// that shall be redirected to http:// 2.) Then [login to view URL] (or [login to view URL], ...) shall be invocted I do not mind if this is done within the configuration files of the webserver or within htaccess - or a combination of these. Root access to the server is available (but cannot be granted to the Freelancer for security reasons). The job: Provide a step-by-step manual (PDF) to configure the server or how the htaccess shall look like (if it's all done within the htaccess only, a sample htaccess is sufficient).