A semicolon is a punctuation mark (;) indicating a pause, typically between two main clauses, that is more pronounced than that indicated by a comma.
I believe the answer to your question is "Next month I am planning a trip to the beach; the beach is my favorite spot to vacation." It uses two clauses in both sentences and it uses a semicolon to separate both of them.
I hope this helps you in your studies and have a great day!