i have a old lennox apartment furnace with air. can somebody please tell me where the coils are?

The coils are inside of the furnace cabinet, you would need to take a panel (or panels) off to get to them. They are often (though not always) arranged in a triangular shape box inside the air handler, close to it's connection to the air return ducts. Since water condenses on them, you can pinpoint their location by the drain pipe which goes from a catching pan or trough located underneath the coils.

Below is a picture or a more recent Lennox air handler unit from its user manual.  Yours will look different but the major components will be the same.