cannot find "/wp-content/mu-plugins" to upload "widget-recent-global-posts-feed.php&q

Hello,

I've followed the instructions on https://premium.wpmudev.org/project/recent-global-posts-feed/installation/ but I cannot find "/wp-content/mu-plugins" to upload "widget-recent-global-posts-feed.php". There's no folder called "mu-plugins". How do I proceed?