The process is not that complex but has several steps in order to get it done. I’ll try to explain it with some details.
You’ll need to configure your droplet/server that will host the websites and make sure that your websites will run/work fine it. That means if your websites are using any custom software/application it needs to be present on the new server here as well, e.g if your sites need PHP 7.2 and newer this needs to be present on the droplet as well. If your sites are normal WordPress sites or similar using CMS you should be fine with either LAMP or LEMP stack droplet. This is of course totally up to you, for example if you’re currently using cPanel/WHM you can easily deploy a cPanel droplet using our one click install for cPanel/WHM from our marketplace.
You need to migrate the files and the databases for your sites over to the droplet as well. You can do that either via the command line or using any FTP client like FileZilla. However the first step will be to configure the sites home directories and the virtual hosts and this process will differ from the web server of your choice - Apache or Nginx.
As for the SSL Certificates this can be done as well. You just need to have the SSL files and install them on the droplet. The process depends uf you have any control panel like cPanel or if you run a droplet without GUI, but in both cases you need to have the SSL files (certificate, cabundle and private key)
Hope this helps.
Let me know if you have any questions.