Is talking with your reseller out of the question? Have you read the Help files? There use to be manuals that explained all this but they are gone (excuse me while I cry my eyes out).  This is all very simple and is explained in the Help files.

There's also a nice class on this on SageU:

100E - Sage 100 ERP - Setting Up General Ledger v2013 - 2014

Purchase this 12-month Anytime Learning course subscription to learn the important fundamentals of setting up the General Ledger module. Whether you are new to Sage 100 ERP, or have used it for years, this anytime learning course will help get you up to speed on define General Ledger options, creating or changing the account structure, and creating account values.