To add an image to a layer in Photoshop CC, follow these steps:
1. Open the Photoshop document where you want to add the image to a layer.
2. Open the image you want to add in another window or tab in Photoshop.
3. In the image window, select the Move tool (V) from the toolbar on the left.
4. Click and drag the image onto the document where you want to add it.
5. The image will appear as a new layer in the Layers panel on the right. By default, it will be named "Layer 1".
6. To position the image on the canvas, use the Move tool to drag it to the desired location.
7. To resize the image, select the layer in the Layers panel and use the Transform tool (Ctrl/Cmd+T) to resize it.
8. You can also adjust the opacity of the layer to make it more transparent if needed. Simply select the layer in the Layers panel and use the Opacity slider at the top of the panel to adjust the transparency.
9. Finally, save the Photoshop document with the added image layer using the "Save" or "Save As" options in the File menu.