Hide wp-admin

Hi

I want to hide/change the wp-admin area.

I’ve used iThemes Security, but I’ve had memory issues with it lately, and it actually seems as a small problem, fixing with such a big plugin.

So I thought there’d be another solution and found this https://www.ads-software.com/support/topic/how-to-change-the-admin-url-or-wp-admin-to-secure-login

But it doesn’t work for me.

Could I be doing something wrong, or has something changed, that would require another solution with WP 4.1?