Hi Fanny!
Thanks for getting in touch with us! Let me help you with this topic.
You can change your Events URL slug by navigating to your WP Admin > Events > Settings > General tab. The URL slugs cannot contain spaces, so yes, you should use “-” instead.
To create 301 redirects you can do so manually by editing your .htaccess file, but the easiest way to do this is to use a redirect plugin.
Making those changes should not create any errors. but we always suggest to setup a dev/staging site so you can test things out and make all plugins, theme and WordPress core updates without disrupting the live site.
I hope that helps. Let me know if any follow up question.
Best,
Victor