Hamlet acts 1-3.2

In Hamlet so far there are a lot of unanswered questions, one of the scenes that opens the most questions for me is the scene when Hamlet's father reappears as
a ghost. Their conversation in the woods is very interesting, we learn that Hamlet wants to get revenge on his uncle, but we don't know how. Afterwards Hamlet warns a few others that he may be acted strange. His comment seems out of place of unnesasary, but Shakespeare does this to move the plot along. Shortly after this comment Shakespeare does just as he warned he would, he acts very strange. His family and Ophelia are of the few that know him on a personal level, especially after his father's death, and they begin to notice changes in his attitude. His mother and uncle hire spies and Ophelia and his father agree to this plot cause they all believe Hamlets gone mad, but Hamlet's soliloquies lead me to believe he could be up to something...