How to format EXT4 (or best format) and best hard drive?

I would then suggest plugging both drives into your Vero and use the file manager in settings to do the initial transfer. Although you will be restricted to USB 2.0 transfer rates this would be preferable than a bulk transfer over wifi. The interface may take a bit of getting used to but basically you would go to the right pane and navigate to the new drive where you would like your files moved to. Then in the left pane you would navigate to your old drive and context menu on a folder and select the ‘copy’ option.