Its important to realise that even though the problem may begin as relatively minor, it may deteriorate into something worse:
For instance, if the linkage is loose or bent, some parts may fall off, making a quick home repair difficult or impossible.
The linkage should lead down through the firewall to the transmission, and hook up on its side near the middle of the car in front of the driver's seat.
It should be visible from below, if you can jack at least one side of the car up higher, or if you know someone with a 'trench' style bay you could walk under the car and examine it from below. Alternately you could borrow a hoist and then look under the car. This will be the natural method of examining and possibly tightening the linkage or adjusting it.
Do you have a friend who can help you with this?