DIY Project with MDF

OK -

I have started mine and using MDF after reading so many threads. Had some trouble and lack of funds. The table will be 4 foot by 4 foot instead of the 4 by 5 like I originally wanted.

I am confused on different axis stuff. So far I have used 3 Axis system that I already have and the new table I want to do more complicated work. Trying to figure out how can I do a 4 or even a 5th axis??

Here is an example type stuff I have worked with:
http://www.rcuniverse.com/magazine/a...article_id=467

Any guidence and advice on how you go about doing a 4th or even a 5th axis would be appreciated. Thanks