Hi Santosh,
As Mr.Gordon say, if you have some knowledge of finance, you can easily set up the G/L accounts.If you want to do G/L Determination you can set this into Administration-->Set Up-->Financial-->G/L Account Determination. There you found 4 tabs. Sales,Purchase ,General,Inventory. SBO listed type of accounts. You have to set account code as per requirement. Second G/L Determination you found in same tree. Administration-->Set Up-->Inventory-->Item Group and Warehouse. you can set the G/L for item group wise and warehouse wise. Using all these setting SAP B1 will do the voucher entries.
But again you should have G/L knowledge to know which G/L set where.
Please browse below link for more help.
http://help.sap.com/saphelp_sbo900/helpdata/EN/45/05bc7324a70489e10000000a155369/content.htm
Hope this will help you to resolve your issue.
Regards
Manoj