Inspiron 3650 : How to add a hard disk

Hi

I bought an Inspiron 3650 and I would like to add a hard disk.

I ordered a "compatible" hard disk in the Dell-shop, but it cannot be added because:

The 3.5" model that I received does not fit next to the disk that came with the PC : too large
and I don't see where it fits at all.

There were no cables (sata and power) delivered with it

There was no installation instructions delivered with the disk
- Where to put it
- How and where to connect the cables on the motherboard (that is if the cables would have been delivered in the first place)

As you can see from the above, I have a problem :emotion-1:

Can anybody help me with this please ?