301 with multisite subfolders

Hello,

Hopefully someone can clearify some points for me. I want to 301 redirect mydomain.tld/blog to mynewdomain.tld in my multisite (subfolders)

Can I do this with a plugin let’s say “page links to” or Yoast or do I need to touch the htaccess?

When I did a 301 redirect successfully, does this mean that the browser changes to the new url automatically (or is this just for the search engines)? If not, how can I achieve this? See, I want the browser to redirect automatically to the new domain if somebody clicks the old page in google. I tried the plugins but neather did work that way.

Thank you very much!