Cathy,
Different language versions of the "continue" and "go back" images are available in MediaLab 2012 (not sure about earlier versions) in the C:\MediaLab\Graphics folder. Hebrew is currently available; Arabic is not. Replacing the "continue.bmp" and "goback.bmp" files in that C:\MediaLab\Graphics folder will change what is displayed in MediaLab.
As for making your own, Paint is a program that comes with Windows that can create/edit image files. Use the existing continue/go back images as a template, and try to match the sizes and layout as best you can so it displays correctly.
I've attached the Hebrew files in case they are not available with your version of MediaLab.