Stereo Line input to laptop

I have recently purchased an inspiron 15 5518 laptop,  to replace a Dell desktop which died.

One of the things that I want to do, is to digitise stereo vinyl records and to do this I have downloaded an application onto my laptop, Spin-it-Again, by Acoustica.com.

With my old desktop, this was not a problem, I used a stereo cable to connect the signal output from my Hi-Fi to the stereo line-input jack socket on the PC.  However, with the Inspiron laptop, there is only one mini-jack socket.  It hould be for headphones/microphone combined, this suggests that the socket (may) be 4-connections.  If there is a plug-socket mismatch, then this may explain why I am only getting mono audio into the laptop.

I have just wasted about an hour with Dell's technical assistance, ending with the person on the other end saying that they could not help me and referring me back to the retailer.  I really don't think that the young salespersons in the retailer can answer this type of question.

So, can anyone here please help.  Firstly, how many connections does the jack socket have?  Has anyone successfully input a stereo audio signal into the a laptop before?

Thank you