This document provides instructions for setting up a radio stack in a default aircraft in Microsoft Flight Simulator. It explains that the radio stack can be accessed by pressing Shift 2. The user needs to ensure the Com 1 button is active and then use the tuner knob below the standby frequency to change the number on standby. Once changed, the user clicks the standby button to switch the new frequency to active, allowing them to communicate with air traffic control by pressing Caps Lock.