Assuming the template is a .psd file?
What version of Photoshop are you using?
Does the template state what version it was made in?
Could you post a screen shot of the layers panel with the file open?
Amazon KDP templates come as PDFs and PNGs. You do not insert anything into them, they are simply to be used as a reference for where and where not to place images and text.
Open up one or the other template file in PS and build your design using layers. When finished, delete or hide the template, flatten the PSD and save in whatever format Amazon specifies. (My experience has been with CreateSpace; I save the final submission file as a PDF.)