There are three tabs on the H bracket.  One is the corner top
tab, about 1cm wide that releases the H bracket from the case.
That requires you to squeeze together the top tab and the far
side of the H bracket, pulling up on the white lifting band.
Each drive also has a tab about 3cm wide at the front of the
drive carrier plate that locks the carrier plate into the H bracket.
Those two tabs release the carrier plates, fairly easily, but the
ears on the carrier plates that slide into the slots in the H bracket,
on each side have very tight clearances, depending on the screws
used to mount the drives to the plates.  They can be a 3 handed
operation to remove from the H bracket if they are tight.  Once they
are removed, bending the ears down towares the center of the H
bracket will ease the tighness and binding of the plates into the
bracket.  I guess about 3 to 5 degrees of bend on the ears is
sufficient, and works in my hands.  That is just enough bend to
ease the tighness in the slots, a bit.  Apparently, the mounting
screws cause s slight separation of the carrier plate from the H
bracket and that puts drag on the drive side of the carrier plate
ears against the H bracket slot.

Bob Keys