Does anyone have the steps for this?
There are two ways to key the radio - VOX or PTT. VOX is the easiest to set up.
In the Winlink Ardop session select Settings > Radio Setup and radio model to FT-99/A, mode USB, serial port to your Enhanced port. Set PTT port to External. Select Settings > Ardop TNC Setup and set your capture and playback devices to your radio CODECs.