That's where I'm lost!
I started by using a micro SD module but was told I could write to EEPROM 100,000 times before wearing it out.
I read the last known position of the steppers (it's the same for all motors, so just one integer) from EEPROM or SD card. I want to move all the steppers, at the same time, from their current position to a new position. If the new position > current position then turn forward else turn backwards.
I hope it's clear now.