Hardware setup
The minimal audio hardware needed to be able to setup the project is just headphones connected to your computer. Then, do not forget to select the headphones output in the Audio settings panel.
If you want to setup several users, you will have to use a sound card with the right number of outputs. For instance, if you want 2 listening posts, you will need a sound card with 4 outputs (2 posts * 2 channels), like a Scarlett Focusrite 4i4. Connect the sound card to your computer with the usb cable (you might need to download a driver in order to use the sound card). Then, you just have to connect the outputs to headphones amplifiers, like the Behringer HA8000 or the Behringer HA400.
With a Behringer HA8000 :
With 2 Behringer HA400 :
To have your own local network, I recommend using your own router. People will have to connect to this wifi network before getting access to the web interface.