a couple of = two persons and things joined or related in some way
The monkey has a couple of bananas.
He arrived a couple of days ago.
Bobby has a couple of pens in his pocket.
A: Have you been to Europe?
B: Yes, a couple of times.
a long time ago = once upon a time; many years ago; ages ago; long ago
A long time ago, dinosaurs lived on the earth.
A long time ago, there were no airplanes.
My grandfather was a pilot a long time ago.
A: When did you go to Germany?
B: I went to Germany a long time ago, in 1963.