My example table below talks about these things. This is a cell. Right click anywhere to get menus to make changes. Don't worry if you run out of room, the table will adjust. Just press enter.
Rows go across and colums go down.
When working with the menus, never use pixels. Always use percent. It works better that way. To highlight a whole row you can left click and hold the button down and move it along the row. If you need to highlight a colum you just move your mouse to the border and a small down arrow should apper.