How can I add a graphical arrow on screen to an imovie project

Working on a recruiting video for my daughter, and I am trying to mark her position on screen with a graphic "arrow" that identifies her at the beginning of a play. Can this be done in iMovie? If not, I have FCP, but no clue how to use it.

I don't know much about iMovie, but for most editing systems, the general process is:
1) make the graphic, with transparency, in a program like Photoshop. You'll have to save as a .psd or .png file.
2) in your editing program, put the graphic in a video track above the source video track
3) align the graphic so it points to what you want

Does that help? Maybe someone with iMovie experience can offer more specific advice.