Please follow the steps: Step 1: Download SeaMonkey to Gmail Migration Tool on Windows Computer. Step 2: Run the app and go to Open button. Step 3: Please add your SeaMonkey files / folders. Step 4: It will load them on left panel. Click on folder to get the complete preview. Step 5: Click on the Export button and choose Gmail. Step 6: Finally, enter your Gmail credentials and click on Save button.