Indexing of arrays starts with 0. Here's an example of a two-dimensional array and some assignments. From this example you should be able to work out the indexing scheme. Make array has a number of additional features we will not cover here. Initial contents are specified with a list of elements having the required sublist structure to match the array.
Programmers like to use arrays because they give uniformly fast access to all their elements.
In general, however, arrays are less flexible for representing structure than lists. No array can concisely reproduce this structure, since it must have a uniform number of elements for each of its dimensions.