GST Calculation for Dropshipping Business

I need someone highly proficient in GST regulations and calculations to analyze my GST reports for both B2B and B2C transactions from December and January. My business revolves around dropshipping with Roposo and I recently got GST. The deliverable should be a detailed report breakdown of the GST amount I have to file. Keep in mind, I just need the calculation, no filing assistance required. Ideal candidates would have significant experience handling GST for eCommerce businesses. Proficiency in Excel and attention to detail are also highly valued in this task.