Answer:
Different puctuations can help identify the authors tone by seeing how it's used in the sentence and context. Paying attention to the way the author uses puctuation can help you determine and see how they're trying to get the thought across to you, or how the character is speaking.
. = A period can mean a neutral idea, it could be an imperative of declarative sentence.
! = An exclamation mark usually shows excitement, eagerness, etc. These are used in exclamatory sentences.
? = A question mark indicates a question. Pretty self explanatory. They are used in interrogative sentences.
Let me know if you want any examples, or have any questions! Good luck :)