When they stole the radio,,did they cut the wires going into the radio,,and now you have a bunch of cut wires hanging out of your dash ?
If the answer is yes,,then you need to know that the remaining wires are going to be shorter than when the factory connector was attached.
Do you plan on putting in another factory radio,,or do you plan on putting in an after market radio ?
If your going to put in a factory radio,,then you will need to add an extension to each wire,,you may need to make each extension from 4 to 10 inches long.
Make sure the extension wires are the same guage,,its best to use rosin core solder and shrink tube to make the connections,,get this at radio shack.
You will also need a factory connector,,get this at the dealer,,some factory radios require 2 or more connectors,,some connectors come with pins installed,,some don't,,and you will need pins.
Now if you use an after market radio,,then it will come with a pre-wired connector,,all you have to do is connect the pre-wired connector to your factory wires
Many factory stereo systems are set up like this: Lets say you have 4 speakers,,then 8 of the wires are for speakers,,if your radio had in internal clock and/or memory function,,then you will have 2 power wires,,one power wire is " hot " all the time,,and the other power wire is " hot " only when the ignition key is on.
One of the wires will be for radio ground.
If your car has a power antenna,,then there will be an extra wire for that purpose too.
hope this helps.