Found the simple solution. Instead of "Render" I'm supposed to click "Export and Share."When I click that it "saves" (in my own words) out the file as a video time lapse. And gives the results I was after. I thought Render meant to grab everything on the time line and save it as one cohesive video.But sounds like Render is more for creating preview videos of your work, rather than viewing your work in Premiere, where it might otherwise be choppy. (?)What does the term "render" mean? and how is it accomplished?...
(On edit: It appears we were typing simultainously! Since you found your answer, I could delete what I wrote. But, since others might read this, I will leave it. )
I don't have a GoPro, so my experience with this is limited. Most cameras with a time lapse function build the video in the camera.
However, time lapse video can be made in most video editing software with still images. It works like a slide show with very short display duration.
The basic steps in Premiere Elements:
1. Set the Default Still Image Duration in Preferences. It will take some math or experimentation based on you project and output settings to figure out the right setting.
2. Bring the images into the project through Add Media. Drop them to the timeline. Pay attention to the naming because they may not be in the sort order you planned. Some will rename the files with a 001.jpeg, 0002.jpeg, etc sequence.
3. Play the preview. The "Render" button may be needed to create a smooth preview. The "Render" button does not create a final product, it creates preview files for smooth editing.
4. If you don't like the play rate you can delete all your media and start over with a different Default Still Image Duration. Or, you can select ALL the images on the timeline and try the Time Stretch (and shrink) tool.
5. When you like what you see in the project, use Export and Share to process, encode or "render" an playable MP4 file.
Note that the only place the "render" word shows up in Premiere Elements is as a choice to make previews smoother. The indicator for when that is necessary is either jerky playback or a line above the timeline that is NOT green.
Good luck with your project! Premiere Elements can make great time lapse videos from a series of stills. A lot depends on the core strength of the computer. Resizing and/or cropping in a photo editor may be necessary. It often turns out that the in camera time lapse shooting is a lot easier.