3) Setup apache to serve your domain using https:
For the proxy specify SSLProxyEngine On
4) Setup apache to work as a reverse proxy using one of the following configurations for your Apache Virtual Host.
5) Create an A record for your domain pointing at your proxy server's IP address. If you have previously created a CNAME record for non SSL please remove it.
For the booking page.
ProxyPass / https://admin.beds24.com/
ProxyPassReverse / https://admin.beds24.com/
5) Create an A record for your domain pointing at your proxy server's IP address. If you have previously created a CNAME record for non SSL don't forget to remove it.