Group
The main thing to remember is that the grids must be read right, and then up. Due to the fact that the map grid is composed entirely of numbers, it's important that you do not transpose them, else you're likely to send someone far, far away from where you needed them to go.
Above: Read the x (horizontal) axis first, then read the y (vertical) axis
Read grid coordinates to a 6 figure level (### “tack” ###) by combining the first 3 coordinate digits representing west-east and the first 3 coordinate digits representing south-north, with the resulting grid having a resolution of 100m.
Read grid coordinates to a 8 figure level (#### “tack” ####) by combining the first 4 coordinate digits representing west-east and the first 4 coordinate digits representing south-north, with the resulting grid having a resolution of 10m.
Recognise points of elevation and hill numbers:
Read contour lines using the 2 types contour intervals marked on map:
Recognize the gradient (steepness) of the terrain, based on the spread of the contour lines (the closer contour lines are, the steeper the terrain)