I have 50 remote sites that I would like to set up Sinolta on each. Do I need to buy 50 Sinolta Licenses and install them on these computers one by one?

That is one way of doing it. Alternatively, you can purchase an enterprise license with a pool of points. You can have an unlimited number of servers that can authenticate with your enterprise licensing server and run as long as the total number of configured points in your system does not exceed the Enterprise point count.