>found a template on a website called graphic river that was created in ID
1-ask the person who created the template
2-ask an InDesign expert
An InDesign template (if that's what you have…it isn't really clear from your post) is just like any other InDesign document except for two things. One is that the file name of a template ends in .indt, while a regular document's name ends with .indd. The other difference is how the file opens. A template will open as a copy of the file with the default name of Untitled-x (where x stands in for the number of documents that you have created since the last time InDesign was launched). The point is that a template is something you would want to use over and over again, so you don't want to screw it up by saving over it. Also, reusing the same file over and over again isn't good because over time, errors can be introduced that can cause the file to stop working correctly. Since templates always open as new copies, they are more like new documents, but they will have any design elements you want to reuse already in place. You can save over a template if you need to by using the same name and location of an existing template, and if you choose to save as a template rather than as a document.
So, if you have an InDesign template, you can open it, add anything you like and save it as a template with any name you like, and it will always open as a copy, preserving your template for later use (but only if you open and save it with InDesign—and you only mention that you have Photoshop, which won't open InDesign files).
If you are asking can you open the template in Photoshop CC, the answer is no. If you are asking if you can open the template in InDesign and add images from Photoshop CC, the answer will be yes.