trying to work out how to insert art into a mock-up image

Is this what you are trying to do?

1. Open your picture, select it (Select > All), and copy it to the clipboard (Edit > Copy).

2. Open the picture of the frame and paste from the clipboard (Edit > Paste). This puts the picture on a new layer.

3.  Resize and reposition the picture layer as needed to place within the frame. It might help to temporarily lower the Opacity of the picture layer as I have done.  Don't worry about excess picture outside the frame opening. The next steps will fix that.

4. Temporarily turn off visibility of the picture layer.

5. Activate the frame layer and select the frame opening. Here I used the Polygonal Lasso tool:

6. Turn on the visibility of the picture layer.

7. Invert the selection so that everything outside the frame opening is now selected.

8. <Delete>

If  this is not what you are trying to do, please clarify.

suzanne1960  wrote im using adobe photoshop elements 13 and i have a mockup image of a wall with a frame from shutter stock and i can't work out how to insert my art work or picture into this frame? i have looked at a youtube video but they use a different version.

What are the dimensions of the cut-out in the frame and the picture which you are attempting to insert?

Also, what is the resolution of the frame and of the picture?