The exposure meter should always have the line in the center to start with, this should give you the correct exposure or close to it.
The camera meter has a variety of exposure modes including:
Spot meter – takes the exposure from a small area of the lens 10% or less
Centre Weighted – takes the reading from the centre of the lens
Matrix metering – automatic metering that takes readings from lots of areas of the viewfinder and averages them out.