Here’s an example code to do theme activation redirect:
/* Redirect on theme activation */
add_action( 'admin_init', 'prifix_activation_redirect' );
/**
* Redirect to "Install Plugins" page on activation
*/
function prifix_activation_redirect() {
global $pagenow;
if ( "themes.php" == $pagenow && is_admin() && isset( $_GET['activated'] ) ) {
wp_redirect( esc_url_raw( add_query_arg( 'page', 'because', admin_url( 'themes.php' ) ) ) );
}
}