You can copy the images below so you can try it for yourself. You results might not be exact as mine because I changed the opacity settings on some of the layers. Layers 1-7 were all 90-100% opacity on overlay mode. Layer 8 was on normal and about 75-80% opacity. Layer 9 is my base image (background layer).
To do this: Open up your base image or in the case of mine above, bucket fill the background on a new image. For digital scrapbooking, the resolution is at 300 and dimensions are 3600x3600 pixels (my examples here are smaller to save my storage space on blogger).
Once you have the background image, in the image box go to File> Open As Layers> Select the images you want to import. After they load, save your new image as a psd or xcf file just in case there's a problem later.
Then select each layer one at a time and change the layer mode from normal to overlay. Click the eye next to each layer to see what your image looks like without the layer. Also change the way it looks by changing the opacity of each layer.
I've used brushes and erasers on selections of layers in the past. You can add text, making the text layer burn into the image by using layer modes and opacity. Experiment. When you find something you like, flatten your image and save as a jpg. In the quality box that pops up, I always select 100 (default is 85).
**You might have to change settings in your preferences (Tools box> File> Preferences> Environment) to accommodate the larger image with so many layers. I have my "Resource Consumption" settings at 100/100/150/150 and I often clear my undo cache in the dialog box but don't do this unless you know you don't need to back out of some of your changes in the undo levels.
[I hope you understood all of this. Seems whenever I'm doing tutorials I get interrupted 100x.]