Multi-exposure can be set by going to the 2nd screen in the Record Mode Menu Settings. You can select the number of shots from 2 to 9. You can also select Auto EV adjustment, which if "on", adjusts the exposure based on the number of shots you're combining.
When shooting in Live View, you will see an instant review of the shot just taken.
Immediately after the shot is displayed, you can start composing the next shot. The first or previous shot is greyed out and you can now move the full color view of the next shot around until it aligns or overlaps the way you want.
You can repeat this until your last shot in the specified sequence (2-9 shots) is recorded, at which point the camera generates a composite image using your multiple exposures which you can review on the K-7's sharp and detailed 3" display.
It should also be noted that during review you can delete an image and start the multi-exposure sequence again. The K-7 will save the composite image as one file, and the multi-exposures as separate files. Although I did this quick experiment using JPEG file format, you can shoot in RAW mode.
(Note: The lens used to produce these images was the FA 100mm Macro. Action hero figures used for this test provided courtesy of my grand kids.)