How to redirect non logged in users to Login page on Wordpress?

I know this is a question asked million times but I can't find an answer that is either fitting the version of Wordpress now and/or my particular case.

I have a Wordpress website with Buddypress installed on it.

I want that : - Not logged in users can see only the page wp-login.php - Logged in users can access the whole website

I just can't figure it out, it is impossible. Either I change the site address or assign a page, or fuctions... Nothing works, all the time an error or a 404 page error etc...

Basically : you arrive on the website, you are not logged in = Wp-Login.php, if you are logged in page "members"

Thank you !

There are a lot of different ways to do this based on what your ultimate goal is (use WP login page, a custom login page, etc...). You can try adding this to your theme's functions.php file:

if ( ( is_single() || is_front_page() || is_page() || is_archive() || is_tax() )
    && ! is_page( 'login' ) && ! is_page('register') && ! is_user_logged_in() ) {
    auth_redirect(); 
}

Or you can use the plugin, Force Login

UPDATE

Theoretically, you can probably just use this, just haven't tested...

if( ! is_page('login') && ! is_page('register') && ! is_user_logged_in() ) {
    auth_redirect(); 
}