What do we learn from surface of potential energy? is it only the number of reaction steps (No. Also kinetic and thermodynamic parameters. - GS).

^^^so does that mean how fast/slow as well as heat,etc? (Yes. - GS). Also do we learn the same thing from a surface of total energy? (Total energy does not change with reaction coordinates, so that surface would be just a flat plane. - GS).

^^^Does that just mean that the total energy for the reaction is constant and is just measured overall? (I would use the term “total energy of reactants”, which does not change as long as the reactants do not collide with other particles and do not interact with electromagnetic radiation. - GS).