Mass-energy tells spacetime how to curve and curved spacetime tells mass-energy how move.

There is a circularity, but this is true of motion in Newtonian physics, where mass creates a gravitational field and the gravitational field tells mass how to move.

A full self-consistent solution closes the circle.

Local file: local link: mass_curve_motion.html.
File: Relativity file: mass_curve_motion.html.