Coolant Leak 2012 MK6 DSG

So my car just got back from the shop after its regular service. 2012 MK6 DSG. I have a minor coolant leak and the shop said it’s from the “radiator assembly”, I have been on YT and would be confident that I could do the coolant piping and radiator myself. Looking for any advice on how to diagnose this and what to actually repair.