LjasonH on "Call plugin function from button and then forward"

Ello there.

I'm new to WordPress plugin development (new to Php in general) and I'm looking for my plugin to run some if checks and then forward to a new page after a submit/button was clicked.

I am currently running something like:

function plugin_run_function() {
    if (isset($_POST['button-name']))
        if (something == true) {
            header("Location: http://my.com/forumpage/");
        }
    }
}
add_action('init', 'plugin_run_function');

My questions are:
how can I call the function on a button click (does add_action('init', 'plugin_run_function') work)?
how can I redirect to a new page (wp_safe_redirect();)?

Currently I'm just learning so security and OOP style plugin will come later on.

Thanks in advance for the help.