Need SATA cable to add SATA drive. Purchased cable that does not fit

I want to add SATA drive. I now have small battery. I searched for 9530 and found on amazon

It doesn’t seem to fit. Dell says “end of life” and wont help me.

I googled 9530 videos and found some with laptops that look different. Mine has spring loaded door on back hiding two screws.

Owners manual:

https://dl.dell.com/manuals/all-products...

Q: am I not installing properly or is there a different part please.