I have a vivitar telescope and lost the instructions.

You did not say what model or type of telescope you have-- most of the Vivitars are very simple telescopes --- they all work the same way -- there are two basic types of telescope:

Reflectors -- which use mirrors, and the eyepiece is inserted into the side of the tube

Refractors - these "look" like a telescope-- and use a lens in the front and an eyepiece in the back.

Meade maintains a web site for all of their telescopes. Look here and download one that is similar to your telescope under Refractors or Reflectors.

http://www.meade.com/manuals/index.html