That depends on what you mean by the "same pdf." Kami will recognize the exact same PDF, and so your annotations will be loaded on top of it.
If you want to create different copies of the same file within Kami, go to the Open file button in the top right, which looks like a folder.
Next, Select View All at the bottom of the page.
From here, you can manage the copies of the file, and create new copies.