There is nothing to worry about..
Contour lines are imaginery lines joining points of equal elevation above a datum or benchmark. The trajectory of each contour lines indicates the shape of the land formation at that elevation.
Contour interval refers to the difference in elevation representated by any two adjacent contour lines on a site plan. The larger the area, the steeper the slope, the greater the interval between contour.
Just try to visualize the countour in 3-d. and always try to to work with section…