Hi and welcome to Aces High!
You can transmit/receive voice (vox) two ways Mic Channel and Mic Range. Mic Channel allows you to communicate verbally with those others tuned to a speciific radio channel. For instance, on your radio text bar, type 160 into the last entry box on the right, which is marked with a V. By activating the Mic Channel key (we'll get to that in a sec) you can speak with anyone else tuned to ch 160 (within your country) You also have the options of typing anyone's CPID into that box, same country or not, and speaking one on one with them. My cpid is dmdmax (Knight). If your flying Bishop, you can speak to me by typing dmdmax into the radio V box and activating your mic channel key.
Mic range allows you to speak to other countrymen within a range of 5 miles +/- That all said, let's get you set-up.
Open your clipboard, click CONTROLS and then click KEYBOARD MAP. Highlight the GLOBAL button on the bottom left. Scroll down the list of options till you come to Mic Range. Click on it to highlight it. Now use the cursor to click on the F11 key on the keyboard. Click on the SET KEY button. Now scroll down to Mic Channel and select the F12 key. Click on SET KEY and then click on OK.
You are now set to talk on channel or range by depressing the F11 or F12 keyboard keys.
One final tweak, if you have unassigned control buttons on your joystick or throttle, you can use the joystick setup to activate the mic transmit buttons (F11+F12) I'll be happy to walk you through that step once you have your range and channel mic keys set and working.
Sorry if I made that more complicated than it needs to be

DmdMax