Photoshop Elements :: How To Merge Several Rocket Launch Photos To Make One Photo

I took several pictures, seven to be exact of a rocket launch at night, thinking that one long exposure might make some sections of the photo too bright.  The beach is a little underexposed, but that is OK.  how to join them?  I thought I would use the first one as the base and basically merge the others after I take out all of the content except the rocket plume/flare, but when I try this, it puts the rocket plume in the middle of the layer and I would have to manually align the rocket trail, but can't seem to do it very easily.  I'm only trying to cut and paste, and obvious newbie to elements.  I have just upgraded to 12 but still have 9 on my machine if one is any better than the other for doing this type of thing.