ATERET V5501 Roofing Bucket I 50 ft. Vertical Lifeline Assembly, Reusable Anchor, 5 Gallon Bucket, Safety Harness Kit

To be clear you have to screw this though the shingles into your roof to secure? Have I not just created a problem by doing this?

Is the anchor base flexible for different pitched roofs?

What size is the harness? Is there a size chart for different body sizes?

Doesn't this come with the roof anchor? I have 2 packages in my bucket, rope and harness but it appears I am missing the anchor.