Function, purpose of the play within a play in Hamlet***see below

The topic is

What is the function of the play-within-a-play episode of Hamlet? What purpose does it serve in the text? Does this element of the play illuminate some of Shakespeare s larger concerns in Hamlet? If so, how? Be sure to explain how the play-within-a-play relates to one or more of Hamlet s significant themes.

and these are my outline(sort of)

Function  gives Hamlet a chance to know what really happened to his father
Make players to see the play in 3rd person s point of view
And we audiences watch how they react
 Uncover the conscience of the king

Purposeonly thing Hamlet was actually active for the revenge.
Since this play, the king reveals his mind and thought to the audience
It increases tension between the king and Hamlet
From this moment, the king and Hamlet become opponents to each other

Concernshow people get to the truth and how they deal with it

Theme The play-within-a-play in Hamlet advances the progress of the revenge Hamlet is assigned to as well as it shows how complicated revenge is.
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***please write it not using difficult words and sentences
I am in first year so please write it easy

***only material you need to use is

Hamlet (The Pelican Shakespeare) edited by A.R.Braunmuller