For here , you can create all the 301 redirects in a modern way. All you need to do is copy the old link and new link, paste the old link as source URL and the new URL as the Destination URL.
Make sure, the REDIRECT PLUGIN is enabled in the plugin manager.
Save and you are done. Make sure, you always paste the old and new link for the same domain. Redirector Manager only supports 301 redirects from the same domain.