In your pictures...
Provide connectors 1 and 2 with 8 pin PCIe power. Connectors 3 and 4 are 8 pin (or 2x4 pin) CPU power. They are pinned and keyed differently so you can plug them in the wrong sockets by mistake.
I only have 1 8 pin CPU connector and 1 4 pin CPU connector. So, can I use a 4 to 8 pin adapter to make it work? Or I can just use the 4 pins and it's fine.