Sorry, but I don't support the suggested dictionary addition above: it's misleading, incorrect, and would not improve the WRF's English-Czech dictionary.
The problem here is that we don't know what kind of "appointment" is intended because there's no context, and since "appointment" is countable, it would have to be "get an appointment". "Setkat se" means "to meet" in the very general sense of the word (two or more people come together, usually socially) and doesn't refer to "an appointment". It doesn't convey any sense of "get" - domluvit se/si, nechat se, etc., and it's the wrong verb for getting a medical appointment. It's also unclear whether the sense of "get" is "to try to obtain" - nechat se objednat, or "to be given" - být objednán. The relevant dictionary already has entries for "make an appointment with/for someone".