Transferring External HDD Inside Dell XPS 15

Dear all,

I would like to enquire for how to successfully implant a secondary HDD inside my XPS 15 PC. I do recall that this model possesses a spare HDD slot, but do feel free to correct me. I would very much appreciate it if you could send me some simple and brief instructions or a tutorial on how to carry this out without any hardware or software errors - I wish to not experience any technical difficulties since I have a lot of data on this PC. When I say to implant this HDD, I intend to open up the necessary parts of the PC in order to access the respective HDD slot. 

The community's assistance is always highly appreciated.

Thank you.

With my kind regards,

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