I would like a lot of help, I currently serve two different clinics remotely I have a server installed on each machine in my house, but I would like to know if I can serve these two clients with just one server, or if I can install more than one server per PC .
I currently use linux mint
You can run multiple instances at once. I would recommend using docker and docker-compose to make this as easy as possible. The only thing you need to be aware of is you will need to run them on different ports ie: 1 instance on 4242, 1 instance 4243 etc…
And a great resource for how to run orthanc in Docker https://bitbucket.org/osimis/orthanc-setup-samples/ and here is an example of running multiple instances https://bitbucket.org/osimis/orthanc-setup-samples/src/master/docker/sanitize-middleman-python/docker-compose.yml