Help adding drives to DL4100

Hello, i have a DL4100 with two red 4T drives running as a Raid 1

I have two empty bays. I have a few WD green 2 and 3 T drives that i was not using and was thinking of putting two of them into the empty bays as JBOD.

I searched around and could not find any info as how to add drives. Im sorry for asking such basic questions, but i was not sure if i could just slide them in? do i need to shut down the system first? will i be able to format them without interferring in any way with the raid1 that i have? If i put two drives in that are the same, could i format just those two as a second raid?
i think i read somewhere that i should shut down, remove the two drives that i have, add the new ones, format them, shut down, put everything back in, and power up. does that sound right? thank you

I really have no clue what will happen. You have no control over the raid. Design is to convert to raid 5 with more than 2 drives, but since they are smaller that should not happen.
You “may” be able to access them though in diskmgmt.msc and assign each a drive letter

backup before you do anything

I have an EX4100, so this might behave a little differently to the DL4100, but removing the drives may make the NAS believe that it is completely new as there is some configuration stored on the drives. I would ensure that all partitions are fully removed on the new drives you wish to add and then put them into the unit (probably best while powered down, but think the unit is designed for hot swap). Once they are added, they should appear in the dashboard and then see what options you have available.

Hey, forget anything I said LOL. I was thinking you had a DX4000.
Just put the drives in the DL is my vote