12s towing socket

Hi guys I'm hoping your wealth of knowledge may help me as I have got mixed views from practical caravan.

Basically I am fitting a 12 s socket. I have bought a pre wired one from eBay but there is confusion with the instructions.

The written part says to feed 2 wires from the battery live into the relay. However.....
The diagram shows 1 feed from the battery that goes into a fuse then splits into 2 wires which feed into the relay.

The meterials I have been sent include:
5 meter live cable,1 25 amp in line fuse with 2 connections, a relay and the socket and connectors.

As I have got just enough live wire for 1 battery connection, the written istruction part doesn't make sense. However.....
If the diagram was correct why is there not 3 connections on the fuse,there is just enough for 1 in and out connection.

To put another spin on it, the fuse seems to large an amperage for the wire?

How have you guys wired up yours?

Thanks

Can you post a picture of the instructions? Or link to the Ebay item?

Hmm I've tried to upload photos but for some reason it won't let me. The item on eBay is from pf Jones and is called a universal 12s twin upgrade kit for 12 n single towing electrics. Item number 280591322805
Even those instructions are different saying to fit a 30a fuse when they have supplied a 25a!