If you intent to fly with others in DCS, SRS (Simple Radio Standalone) is a must. So get familiar with it and see download and installation information from:
To make it work best with Hornet, I suggest to use one hat for both radios 1 and 2. I use Thrustmaster Warthog, so I have plenty of buttons/hats to use.
I have selected “Coolie switch” from throttle to be as a radio selector. Hat left click for radio select 1 and hat right click for radio select 2 (radio 1 is left radio on hornet and right is number 2):
Now you have a radio selector switches that also work as an PTT switches.