The grid style will display each row of your view within a grid. You may customize the number of columns, though it defaults to 4. A grid looks like this:
row 1row 2row 3row 4
row 5row 6row 7row 8
row 9row 10row 11row 12
row 13row 14row 15row 16
The above uses the horizontal alignment, where rows are added into the grid from left to right. With a vertical alignment, rows will be placed from top to bottom, like this (your row results will appear as columns):
row 1row 5row 9row 13
row 2row 6row 10row 14
row 3row 7row 11row 15
row 4row 8row 12row 16
You can also choose to group a field from the Fields Section. This grouping field will be displayed as a header, and all rows will be displayed beneath it. This style uses a row style to determine what each row will look like.