Pro Tower Plus QBT1250, adding a SATA drive, #1

Hi everyone,

I brought a Dell Pro Tower Plus QBT1250 with NVME M.2 SSD only. I was trying to add an old SATA III SSD but found that the QBT1250 has no drive bay or SATA power and data cables. So I bought a standard SATA data cable and a 15-pin to mini 6-pin SATA power cable (for Dell Inspiron series only as I couldn't find a dedicated one for QBT1250).

However when I connected the cables to the SSD and plugged the data cable to slot 16 (SATA-0) and the power cable to slot 12 (SATA PWR) (see this), the machine didn't power up. I noticed from this thread that the power cable might not be compatible and some pins in the 6-pin connector needed to be swapped.

Has anyone installed an SATA drive to this model? Do I need to swap the pins in the 6-pin connector? If yes, suppose the pins are in the following layout, how should they be swapped?

Thanks in advance for your help!