How to calculate CubicBezierCurve3 control point of two vector3 point?

I am designing how to calculate the control points of CubicBezierCurve3 through two points. I split the two points(AB) into four points ABCD. In order to keep the curve radian normal, I set the distance of the two control points to the vector AD to 5. How to get EF two control points?

Looking forward for your reply, thank you