The Department field is mostly used for ADA calculations and can be ignored in academic classes although it can be used for subject sorting order in standards based report cards.
The Marking System should be set to Letter to support letter-grade gradebooks, Skills for standards-based gradebooks, and NONE for ADA classes.
CBEDS Code should be set to 6012 in elementary schools. Classes with a 6012 CBEDS code are excluded by SchoolWise from CALPADS extracts. CALPADS does not expect academic marks for grades for K through 6. Code 6012 prevents elementary classes from being exported to CALPADS. This prevents needless CALPADS errors. The rest of the fields really do not matter but since the system insists you choose something for NCLB Core, choose Elementary Core. Since the records are not sent to CALPADS (if you use the 6012 CBEDS code) it has no effect.