"What you did?" or "What did you do?" What's the right? I'm confuse, someone can help me?

Points in italki Hi everyone, someone could tell me for what serves the points in italki?

When I must use "comma"? Hi everyone When I must use comma? What's the rule about this?

Presente Perfect Is this conversation right? - Hi, Mari. >Hi, Dave. How was your week? - Was awesome. I'll travel next week. >Really? That's amazing. Have you ever traveled? - No, I haven't. I'm so excited. Did you travel last year? >Yes, I did. - So, bye Mari. >Bye, Dave.

Something is happening In the midnight, I heard something....It was a dog, a adorable dog "screaming" to the moon. So, I enjoy to him and screaming too...the neighboor threw his shoes in our heads. We laughed a lot rsrsrs after cried T_T Please, correct me if necessary.