The first step is to calculate the dimensions on the inside of the garden bed, which is the length and width that is actually usable for planting. If you bought your beds from a commercial source, then chances are, the interior dimensions are probably a little less than the advertised size.
These beds do not need the usual distance between each row because you are not going to walk in the bed to cultivate or harvest. Vegetables can be spaced far enough apart to be able to avoid crowding but be close enough to shade out any weeds.
Each planting square has an address used to identify the square. While the methods for addressing vary, one of the simplest is to use letters for columns and numbers for rows, and the combination of the two identifies the square.
The spacing is such that when the vegetables are fully grown, their leaves just barely touch each other, creating a microclimate in which weed growth is suppressed and moisture is conserved. Raised beds produce a variety of benefits: they extend the planting season, they can reduce weeds if designed and planted properly, and they reduce the need to use poor native soil. Since the gardener does not walk on the raised beds, the soil is not compacted and the roots have an easier time growing.