Redirect users to a different URL the first time they log in.

um_on_login_before_redirect.php

<?php

// Redirect users to a different URL the first time they log in.
add_action( 'um_on_login_before_redirect', 'my_on_login_before_redirect', 9, 1 );
function my_on_login_before_redirect( $user_id ) {
	$first_login = get_user_meta( $user_id, '_um_first_login', true );
	if ( empty( $first_login ) ) {
		update_user_meta( $user_id, '_um_first_login', current_time( 'mysql', true ) );

		// Set a custom redirect URL for the first time login here.
		$redirect_url = '/user/?um_action=edit';

		um_safe_redirect( $redirect_url );
		exit;
	}
}