The layer grid is the grid that you specify on a page layer . By default, a layer has no own grid, but it inherits is from the master page.
The layer local grid consists of optional column guides (vertical), optional module guides (horizontal), optional additional guides, and horizontal and vertical grid steps (nudge).
Regarding nudge, the layer local grid is has the higher priority of the master grid. If the horizontal and vertical grid steps (nudge) of the current layer are different than 0, they will not be overridden when applying another master page.
Horizontal grid step
The horizontal nudg. It is recommended to set it to 0. In that case, the horizontal snap points will be only column guides and additional vertical guides.
Vertical grid step
The vertical nudge. In a regular master grid, all the vertical nudges will be the same. In order to achieve this, the module height must be multiple of vertical grid steps. If this is not the case, nudges may differ.
Additional guides
Additional vertical or horizontal guides.
See also