using DELL 3400MP projector with my Apple Mac G5 computer. How to project?

I have a DELL 3400MP projector and would like to use it with my Apple Mac G5 computer.  How to project on to screen?   I seems to be "searching" and when I plug it into my Mac, the computer asks to setup "an external keyboard".

 

Are there any function keys that need to be pressed on the Apple Mac side?

 

Thanks,

-carmen