Q: Transfering content to used phone

My current phone (iPhone 5) is getting really buggy and the battery is having issues, so I decided I want to transfer the content to another iPhone (5s). There is an available used iPhone 5s in my house, and I don't want to buy a new phone just yet. How could transfer the content from the old phone to the new one?

I have one idea, but I am hesitant to try it. Maybe by wiping the used phone I would have the opportunity to transfer the content.

Any help would be greatly appreciated!