Initial stage in Accoutn determination in implementation?

hii

Can some explain me , what will be the first step in account determination as MM consultant in implementation??

After 4 steps in account determination , like valuation group,assignment with material type , account catory reernce and valuation class.

We wil move to OBYC - configura automatic postings.

First step what i have to do ??

Because here integration will start with FI consultant , who do this OBYC ???

Thanks

SAP-MM