I am unable to find where to put the redirect link. I go

Hi, I am unable to find where to put the redirect link. I go to Network Admin, dashboard, network settings, but I can not find the 'Use Login Redirect to direct new logins to a page of your choosing' option. There is a login bar on the home page. People that try and login there will go to my superadmin login which I dont want them to see as I dont want to get hacked. I am not sure if the login redirect plugin will help with this problem. Please help me.
Thank you,
Inger