Through T.code Obyc, I configure the BSX Key for Inventory Material.  Configure Valutiaon Class, and Valuation Modifier and Given G.L. Account Number and save.
After configuration all these, what are step to configure because I have been Interviwed by this question and I don't know what are next step.

Transaction code : OBYC (in easy access) 
In this transcation we have to specify GL account codes for material valuation created by MM consultants. 

The process in MM is here below:
1) Purchase Order : Tr code ME21N - here no integration required with FI 
2) Goods Issue : Tr Code MIGO - here no integratinwith FI 
3) Invoice Reciept - Tr Code MIRO - here when the invoice is recieved & MM process the transaction based on OBYC configuration system will generate FI document. System also generates Material document as well 
4) Payment : Tr code F110 - Here also the the transcation affects FI 

FI-SD integation: 
This integration done using Tr Code VKOA. here we have to define GL account codes to Condition types. 

Process :
1) SD Raises Sales Order - No implication in FI 
2) SD raises Delivery doc - No implication in FI 
3) SD processes billing - no implication in FI 
4) SD releases billing doc to FI - FI document gets generated (Tr Code VFX3) 
 

The theory of how MM activity triggers A/c posting is:

Each movement type has quantity and value string, which decides what to update. Also each movement type has transaction event key (account modifier) which in turn depending upon valuation grouping code and valuation class decides which G/L account to post.

The flow is as follows:

Material type --> Account Category reference --> Valuation class -->Material.
Movement type -->Transaction event key-->Account modifier.

You have to do the configuration settings using Tr. code OBYC.

Try with Tr.code OMBW to check which G/L accounts are being hit on Plant, Material and movement type.

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