adding memory to 27" 2019 iMac

[macj3]

I have a 27" 2019 iMac,1TB SSD, factory 8GB (2x4GB) memory, Mojave 10.14.6.
I purchased a while ago 32GB (2x16GB) additional memory from OWC with intentions to increase memory to 40GB total. What slots should I install the memory? Do I just fill the two empty slots? or move around the existing chips?
It is now: : A-bank0=4GB, A-bank1=0GB, B-bank2=4GB, B-bank3=0GB
Should it be: Bank0=4GB, Bank1=16GB, Bank2=4GB, Bank3=16GB
or
Should it be: Bank0=4GB, Bank1=4GB, Bank2=16GB, Bank3=16GB?
Or....should I just pull out the 4GB Apple Memory, put the 16GB OWC memory in its place and use 32GB total in the machine?
Thanks in advance for any replies

 

[wilberforce]

For the 2019 iMac, just fill the 2 empty slots.

Either of the the following slot orders are fine:
4-16-4-16
16-4-16-4

The objective is to have the same amount of RAM in Channel A as in Channel B, which you can check by going to:
About this Mac
System Report
Memory

 

[macj3]

For the 2019 iMac, just fill the 2 empty slots.

Either of the the following slot orders are fine:
4-16-4-16
16-4-16-4

The objective is to have the same amount of RAM in Channel A as in Channel B, which you can check by going to:
About this Mac
System Report
Memory

Thank You!