In order to get your HF8 working with MSFS2020 through the HFS software, please follow these steps:
1. Connect the HF8 gaming pad to the PC (either via USB or the 3.5mm audio jack)
2. Ensure that the HF8 is connected to AC Power and is switched, and the light is showing on the Control Box (solid LED for USB mode & flashing LED for Audio mode)
3. Open the HFS program and ensure that the HF8 is showing as "Connected" and that the correct "Mode" is selected. You can also test the motors here, if you like.
4. Navigate to the profile of the desired game and click on the thumbnail. This will bring you to the effects page for this profile.
5. Ensure that the desired effects are turned on (showing green) and that their strength is set as desired. You can also click the arrow at the far right to further customise which motors will respond to that effect.
6. Next, close down HFS (including from the task tray at the bottom right of the screen). And open up MSFS2020 and begin a flight.
7. Open HFS again and follow steps 4 & 5.
You should now be getting vibration feedback from the HF8 pad.