91 corolla stereo wiring

just purchased a sony deck for my car the other day and was ready to install it.  But to my surprise there were no speakers in the car!!! So we bought 4 new speakers and we took apart the panels to find that there were no wires whatso ever but just a +/- connector.  Do we just connect the wire to the negative and positive connector?? or is there more to the installation? All i know is, there is a connetor for the deck so the car probably did have a radio in there once before.  

If the car already has a harness aboard and the wire colors of the harness match the wire colors of the new deck, and the plug fits, then it should be okay.  And if you have original speaker connector plugs at the speaker locations and you want to connect new aftermarket speakers to the original wiring, then you should strip a portion of insulation off the wires that are going into the plug and solder new speaker wire leads to these.  Test for polarity, and solder F-disconnects onto the new wire ends.  Attach to the new speakers.  Tape all your solder joints.Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.