@BuckSkin, as @Morgan_Hardwood said, it’s in the film strip.
So I am in the editor tab, with the film strip along the top of the screen.
I use this technique when I have a lot of images to go through, typically after a day shooting field hockey.
I’ve actually found that digikam works well for me in this instance, as I’ll tag and rate the images in digikam. Once rated, I’ll filter on the stars, typically just the one, and create a new folder and drag those into a ‘filtered’ folder.
I’ll then open RT up and go straight to the folder working through the processing there. Given the large number of photos and some that simply don’t make the second viewing, I’ll star these in RT and use the above method of once completing all images, I’ll filter in RT and from the film strip, ctrl-a ctrl-b to move to the queue.
For other times when I have a few photos from a smaller set of images, say out in the back yard, I come back with 20 or so, I’ll not bother filtering the images. I’ll open RT go straight to the editor with the film strip at the top, open each image, if it’s a keeper to be processed, I’ll make my changes, star it and then ctrl-b to the queue. Once done, just flick over to the queue tab and start it off.