This scene is of course a very crucial one for the development of the rest of the play - Hamlet meets with the Ghost, who he believes to be his father's shade, and the Ghost tells him how Hamlet's father was killed and then makes Hamlet swear to revenge him. It is crucial for a number of reasons, as it drives the rest of this famous tragedy and also raises an important question of whether the Ghost can be trusted. Note how other characters and Hamlet himself later on in the play wonder whether the Ghost is truly his dead father or a messenger of darkness sent to spur Hamlet on his path to self-destruction.
There are lots of examples of metaphors used in this scene, so I will pick out just a couple. Firstly, consider how Hamlet responds to the news that his father was killed by murder "most foul, strange and unnatural":
Haste, haste me to know it,
that I with wings as swift
As meditation, or the thoughts of love,
May sweep to my revenge.
Note the implied metaphor here - Hamlet urges the Ghost to tell him more quickly so he can gain his revenge like an avenging angel - the words "wings as swift" and "sweep to my revenge" show how Hamlet imagines himself like an angel avenging the death of his father.
Another metaphor that is used just a bit further on by the Ghost is one that describes Claudius. The ghost calls him "that adulterate beast", which clearly expresses his abhorrence at Claudius for first killing him but then adding insult to injury by stealing his wife as well. The metaphor here describes Claudius to be sub-human - a kind of animal that cannot control his lust and has no moral principles to guide him with.
Hopefully this will help you in identifying a few more. Good luck!