For VNC, you need to install the VNC client to the workstation you're remoting from and install/configure the VNC service to the system you're remoting to ("configure" also includes setting requisite firewall and other security exceptions). This also sort of assumes that your Linux-based target has the graphical desktop components installed in the first place (low-likelihood with a secured server kind of build profile).

Other remote access options would be:
* SSH-based CLI-only logins
* Use of an XServer on your local system so that you can do XClient redirection from the remote system to your local system (this can be individual windows or a full desktop via XDM or even SSH-tunneled XNest)
* Remote console (specifics will depend on the hardware capabilities of the remote system - such as whether the system is a physical or virtual server; if physical, whether it's using something like IPMI, iLO, DRAC, etc; if virtual, what the virtualization framework is)

Probably some others I'm missing that are rarer use-cases.