If you would give details about what types and models of switches you are using, as well as the type of phone system it would help you get a usable answer. Generally a managed switch should be able to be “managed” from anywhere on the network. If you would supply the details of your phone system, someone here might be able to help, or direct you to a site that could give you the information you are seeking.
A managed switch will provide a means for connecting to it remotely via protocols such as telnet, ssh or http. Telnet and ssh will provide a menu or command line (CLI) driven interface as opposed to http which will provide you with a Graphical User Interface (GUI). You’ll make changes to the switch configuration via the interface supplied. In order to connect remotely you’ll need to at least configure an IP address on the switch by physically connecting a PC to the switch via it’s console port. The switch admin guide should have the specifics on how to do this.
The default configuration will get you up and running and your workstations connected in many switch platforms so you may not need to change the switch configuration at all. It may not be the optimal configuration, but it makes it easier to get connected.
If you can supply your switch models we may be able to assist more.