What I did was I bought a wildcard SSL certificate from GoGetSSL since I need to secure multiple subdomain.
Then after I was able to setup the SSL certs on my website's server, I encountered a problem in ChurchOnline platform since there's no option to force users to use https instead of http in the settings.
I emailed support and they told me to use Heroku app etc etc etc.
Good thing that our site mbbe.org's nameserver routed through Cloudflare. So I was able to setup under Page Rules option that my http://live.mbbe.org should be force to use https.