This is explicitly related to WordPress so please read this post on how to deal with this issue: https://wordpress.stackexchange.com/questions/107901/remove-the-blog-slug-from-wordpress-multisite-root-node
No, it is not possible to edit events from sub sites.
Before starting to use this addon you should have a network WordPress Multisite. please follow this external link: https://multilingualpress.org/docs/how-to-install-wordpress-multisite/ to create Multisite (WordPress Network).
Let me know if you have any other questions in the comment area.