Download the WPMU DEV Dashboard plugin

Hi there,
When I initially put in my WP site it said the free trial was only for WP users with a trial account. Confused as to what this means. I would like to use the tutorial videos on WP to train myself on how to use it. I tried to download the plugin instead, and the download link prompted a download of a folder of coded things I can't read and no way of installing a software onto my MacBook. Please advise, and speak slowly :wink: