How to reformat my WD pasport studio

I am trying to install my WD my passport studio, but it keeps telling my i need to reformmat it. how do i do this?

Install it where? The passport studio is formatted for Mac’s out of the box, if you are trying to use it under a Windows PC, you need to format it. Check the link below for the steps, but note that it will delete any files that you might have saved.