Hi Sai,
Lets say A holds 70% of B and B holds 60% of C. So when consolidating at A by direct method it will be 70% by group method it will be 42% (70%*60%).
Method update, the method of consolidation will be updated based on the method rule defined in method for e.g.,>50% purchase method, >20;<50 equity method etc.
Remaining two are self explanatory.
Hope this helps.
Regards,
Kalyan.