new sand point well - smelly cloudy water

We put in a sand point well about 28 feet deep. When we pumped water it was grey, cloudy and smelly. Help!!

Also we have been told that a new well should be pumped out for many hours before it can be used. Is this necessary and do you think it would help? Or is this just trying to accomplish the same effect as shown in step 7 of these instructions:

http://weather.nmsu.edu/hydrology/wellpoint2.htm

You must pump the Well until it's clear and sand free.

bob...