_1. Purchase C6220/C8220 with 18 pin plug (onboard sata ports)
LINK HERE
Yes
_2. Purchase 24 ATX + 8 pin to 18 pin mini dell
LINK HERE
Yes.
_3. Plug in 18 pin mini to motherboard
Yes
_4. Plug in 24 pin atx psu to 18 pin
Yes
_5. plug in sata ssd with boot os?
Yes
Step 6
You also need to close 2 pins in the PDB control connector - a small one with a gannum of 2 mm contacts - in order for the board to turn on.
See here for a diagram
https://i.imgur.com/iFB5Dd3.jpg
The jumper between the two contacts is required, the rest is not.
Then you need to connect the VGA monitor and USB keyboard and mouse through the hub, then turn on the power on the block with the button and the message should appear - the "memory configuration - done", you have to wait a long time, then the Dell logo will appear, enter the BIOS and adjust the disks.
If the board is turned on - the power button on the board edge is green - there is no image with an inscription - you need to either connect an external video card (if an external video card is installed - there are no messages about memory settings and the screen is millet black for a long time, then only the Dell logo) or reset bios taking out the battery and setting the jumper, it is written about it in the subject earlier. If after that there is no image anywhere, then the board is most likely broken.