How do I draw arrowheads in PS CS2

How do I add an arrowhead to the end of a line, and adjust its size to my liking?

PS Help says to select the line tool (I can do that) and then select Start (where is this 'Start'?) and that the shape options will appear "in the pop-up dialog box" (where is this 'pop-up'?)

When you select any tool in Photoshop, you'll see the tool's settings options at the top of the screen, in most cases as a horizontal series of buttons and pull-down menus. For the line tool, you'll see that the settings are arranged in four sections. All the way to right of the third section, you should see a small black triangle pointing downwards. Click on that triangle, and you'll pull down a menu, showing the arrowhead options.

The "start" thingie that you asked about is just one of the checkboxes on the arrowhead menu. You can choose to put arrowheads at the start and/or end of your line.

Thank you. It was that tiny little downpointing arrow I missed.