A compound sentence is two sentences joined by and, but, or.
I like lots of stuff on my pizza, but my brother wants only cheese.
Last weekend Dana went to a movie and she also studied for a test.
If you put two simple sentences together correctly, you have a compound sentence.
I was hungry. My mom made me a sandwich. ~~> I was hungry, so my mom made me a sandwich.
Jack ran up the hill. Jill came tumbling after him. ~~> Jack ran up the hill, and Jill came tumbling after him.
The ways to connect simple sentences to make compounds are these:
Let us know if you have more questions.