The terms for different stages of water boiling are not universal. You have to imagine what they mean. A brisk simmer comes just before a low boil. A pot is simmering when you get a lot of small bubbles.
A pot is simmering when it is bubbling, but the bubbles are breaking under the surface.
steaming - water vapor is visible coming off the surface, no bubbles simmer - just at the "bubbling" point boil - bubbles breaking at the surface; high evaporation rate.