Trained models are saved in the following folder:
where NN is version number of your Dragonfly (e.g., Dragonfly41 for version 4.1 and Dragonfly2020.1 for version 2020.1)
Copy the folder of the model that you want to move from the first computer, and paste it to the same location on your second computer. Start up Dragonfly on the second computer and you will find the model ready to load.
Tip: You can input %programdata% in the Filer Explorer location bar to get to the ProgramData folder, which is invisible in Windows by default.