Increase the ladder at least a few toes above the roofline and tie it to the eave, so it won't shift. Never step on any rung that extends higher than the roof. On heat times, self-stick underlayment will stick to thoroughly clean decking without the need of fasteners. Fasten it https://marioudmvd.dreamyblogs.com/29203635/the-smart-trick-of-metal-roofers-that-no-one-is-discussing