Well, first, make sure you have the latest version of Snapchat. Then, when you view someone's story, look for something like a 'Share' or 'Add to My Story' option. Sometimes, it might be a plus sign or a arrow pointing out. Just tap on that and follow the prompts.
Yes, you can. On Snapchat, there is an option to share someone's story to your own story. Just look for the share icon when viewing their story. However, always make sure you have the appropriate permissions or it could be considered rude or a violation of privacy in some cases.
Generally, you aren't able to share someone else's Snap story on yours. This is to protect the privacy and control of the original creator of the story.
It depends. If you are talking about in a creative writing or narrative sense, you can draw inspiration from someone else's story and incorporate elements of it into your own. But you must do it in an ethical way, not plagiarize. For example, if someone tells a story about a journey through a foreign land and the challenges they faced, you could take the concept of facing challenges during travel and create your own story set in a different location with different characters but the same underlying theme.