Depending on how it is to be output, the printer can usually do the set up for you. If the spine is going to be a different color and not contain the same graphics as the front on back, then it’s even easier. I would set up the front and back as two separate spreads with any needed bleeds or whatever. Then, set up the spine separately with lots of extra bleed area. For instance, keep the text within 1/2″ or whatever you think the minimum spine thickness would be, but have, say, an inch of bleed on top and bottom (the area running to the front and back covers). If you’re doing a PDF for final output, it gets even easier…just create the PDFs with the full amount of bleed…in the final output, the person outputting can reduce the bleed to whatever they need. If you are doing PDFs, you can combine the resulting PDFs into one file. Best bet is to talk to the person doing the final output and work out a gameplan.
Erica Gamet
Digital Dimensions
https://www.digi-wizard.com/learn
“…for there is nothing either good or bad, but thinking makes it so.”