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 1 | row 2 | row 3 | row 4
row 5 | row 6 | row 7 | row 8
row 9 | row 10 | row 11 | row 12
row 13 | row 14 | row 15 | row 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 1 | row 5 | row 9 | row 13
row 2 | row 6 | row 10 | row 14
row 3 | row 7 | row 11 | row 15
row 4 | row 8 | row 12 | row 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.