Example 1
Maria had the day off from work, so she watched an Orange Is The New Black marathon on Netflix.
In this lazy (and super-relatable) compound sentence, a comma and the conjunction so are used to join two simple sentences.
Example 2
We should call a repairman to fix our washing machine; it keeps shredding all of our underpants.
Here, two simple sentences are combined with a semicolon. Ooh, fancypants. (Unlike the poor panties.) Semicolons are a great way to show off your mastery of sentences; just remember to save them for when the two sentences that you're connecting are closely related in content.
Example 3
June's favorite actor is Al Pacino, yet she's never seen The Godfather.
We're going to make you an offer you can't refuse: learn how to build a compound sentence. Here, the comma and the conjunction yet are used to join two simple sentences and create a compound sentence.