How can i know when i can execute what functions of wordpress?

I like to do a bunch of stuff only on homepage and archive pages

i am working with the genesis framework (not really matters i guess)

if( is_singular() ) {
    wp_die('functions.php');
}

add_action( 'init', function() {

    if( is_singular() ) {
        wp_die('init');
    }

});

add_action( 'genesis_before', function() {

    if( is_singular() ) {
        wp_die('genesis_before');
    }

});

only the 3rd get executed, i looking for some reference about that i run into some issues like that before. How do get get to know the wordpress scructure better without digging into the source files?

Install my plugin T5 WP Load Order. You get a long detailed list with all available hooks, files, constants, classes, functions and global variables – ordered by first appearance.

Whenever you’re in doubt create such a list for the page you are working on, and look up what you need.