Here's a breakdown:
* Two complete sentences: Each part must have a subject and a verb and express a complete thought.
* Connected with a comma or conjunction: You can join the sentences with:
* Comma + coordinating conjunction: (for, and, nor, but, or, yet, so)
* Semicolon: (;)
Example:
* The sun was shining, and the birds were singing.
* I went to the store; I needed to buy milk.