Orienteering map, simalariry to the compass, very like an ordiry one. Again, the only difference is the scale. Also orientering map has different details included. There are a few green colours, describing how 'fast' is the terrain in the certain place. The more dark the green colour is, the thicker the forest is.
White colour means the 'fastest' forest.
That would be a control point all about the theory. Now a few words from the technical point of view. First thing is how the control point looks in 'real life'. Usually it is made of two pieces of pipe welded together to make a T shape. Below the punchers there is a sign with a number of the control point.