How to properly plug, what order, the sata connectors from a dual HD

I have just opened my mac, cleaned the hard drive fan, and a connected my two hard disks in different sata ports, but i have no idea in which way. I have a dual hard disk system with the original hard disk and one ssd i added in a tray in place of the dvd i removed.

Previously, the connections were as they were originally: sata conector pluged in the original place for the hard disk, sata connector pluged for the dvd, that i use now for my ssd.

i wanted to use the full capacity of my ssd so i connected the sata II in the sata III socket of the motherboard.

but something went wrong so i replugged the two of the sata connectors and i dont remember which one is in which place. But i am sure i they are both connected in the sata III plugs, but i dont know where is the hdd and where is the ssd plugged.

now i start my computer but it wont boot. I cab access chose boot from via the alt key at startup but it wont boot from neither, not from the ssd nor hdd.

Apple logo shows up, but it shows like traffic sign after a while and cannot start. The same from the both hdd and ssd.

my question: is there any particular order i need to follow when connecting two hdd/ssd in terms of sata connection port number?

can you advise how can i resolve this issue?

thanks