Once you have reached the required I.E Min and Max you will be able to enter Heaven. The barriers to enter begin at 94,37,10 in the Eastern Land.
Below is a general guide of each part of the zone.
Within heaven you will find the entrance to Hell (13,16,13), To enter hell you need to reach the minimum required level of 125,000.
There are many zones located around hell, below is a guide to help you find the zone you are looking for;
EXP / Gold Zones: