Need help to change multiple criteria from if function to Case function.

Hello Experts

I am using if function to generate a code. I am not sure how to convert to by using selecting the case for 3 variables.


=IF(AND(O4="NONE",R4="YES"),"SLB",IF(AND(O4="NONE",R4="NO"),"B",IF(AND(O4="GAL",R4="YES",K4<>"M"),"SLG","G")))
1. Criteria based on Finish. 2 options only in this criteria "NONE" OR "GAL".
2. Criteria based on Slot. 2 options only in this criteria " YES" OR " NO".
Depends on criteria 3. If metric slot is ALWAYS "NO".
3. Criteria based on Thread. 2 options only in this criteria for Metric " " or "X"

scenario
1. METRIC, NO, GAL RESULT "G"
2. NO METRIC/METRIC, NO, NONE RESULT IS "B"
3. NO METRIC, YES, NONE RESULT IS "SLB"
4. NO METRIC, NO, GAL RESULT IS "SLG"
5. ALL ELSE CONDTIONS RESULT "CHECK THE SLOT, FINISH VALUES"