Utterly confused and stressed about Non controlling interest

Hello

So im studying consolidation. I have reached at non controlling interest. I am confused on how to calculate NCI for acquisition at start of the year vs mid year acquisitions.
From m y understanding, Fair value of NCI + NCI with retained earning post acquisition = NCI that goes into CSOFP and Goodwill? Is that for start of the year or mid year Goodwill? Can someone please simplify it for me? If we need two different formulas for start of year and mid year, please write the two different formulas clearly for me?
Thank you very much.