big sur 11.3 update help

Hey guys, I want to update my mac os to 11.3, my current mac version is 11.2, OC is 0.6.5
Question 1: Should I first update the mac or the opencore?

Question 2: I need help updating OC from 0.6.5 to 0.6.8, can some one explain the process?

Question 3: Opencore sanity checker has not updated it's website it's still showing 0.6.6 and not 0.6.8, any alternative to this would be appreciated?