So basically... Allegory is a longer version of symbolism. It's almost like there are two stories happening- the actual story and a story being represented by the people and objects in the story.
For example... a story about a little kid who finally gets to visit a father he never knew... just to find out that his dad is a butthead. This story could be an allegory for crushed dreams... the kid representing hope and ambition while the father represents a harsh reality.
I guess to help your question specifically, just try and find out what the elements of the story could be representing in Socrates story.