What does it mean when someone says that a 65 ford mustang needs timed and tuned and how do you do that. It has the 289 engine in it.

It means you need to replace some parts. When doing a tune up you should replace the spark plugs, distributor cap, rotor button, gas filter, air filter, change the oil and filter if it hasn't been done recently, and the plug wires if they haven't been done. The oil should be changed every 5,000 to 7,500 miles.
You need a spark plug socket to change the plugs and a timing light to set the time along with a few general wrench's and screw driver's.
If you are going to try this yourself then you should get a service manual for the car, Chilton's or Haynes have good ones that will contain the information you need to do it. MAKE SURE that you only disconnect one spark plug and wire at a time and replace them before you move on to the next one. Otherwise it might be wise to take it to a garage and have them do it for you. It shouldn't be overly expensive, a mechanic should be able to do it in a couple hours at most, unless he ran into difficulties. Tune ups need to be done on a regular basis depending on mileageand an owner's manual would be a bonus here. It would contain the intervals you need. Hope this helps.