Hi Bill,
My template was a lot of trial and error. There must be easier ways but I'm too stubborn/lazy to read the manual. So forgive my coarse solution.
First to create the Layout, I had to create a custom paper size (I chose 10"x10"). To do this, I had to go to the Printer Properties for my printer (Canon MX340) and choose Page Setup. From the list of paper sizes, there was an option for Custom. Once chosen, it gives the option to enter in page dimensions.
Now I get fuzzy as to the exact order of things. In the Print module of LR3, there is a Page Setup button (also in the File Menu), where you choose the page size - Custom is chosen and a 10x10 blank layout is on the screen now. On the layout commands on the right of the screen, my settings are Custom Package for layout, Inner Stroke checked 3.8pt, Grid Snap "Grid", Cells (4.6"x4.6") - to create the 4.6" cell, click the arrow by any of the "Add to Package" buttons and a menu pops up where you choose "Edit" and enter in the dimensions. As you click the Cell button, it is added to the blank layout.
From there, it was a case of trial and error of moving the cells around - making sure they were aligned.
The images must be square and I think they will zoom to fit. If the image is not square it will size for height but not width and overlap other cells.
On to printing, in the Print Job section of the right hand panel, there is an option to choose "Print to:". I chose JPEG File.
If you want I can email you my template, as coarse as it is. Someday I will learn the elegant way of creating templates but for now a blunt hammer is my approach.
I'm a Windows user by the way.
If you have any questions, I am glad to help as much as I can.
Cheers