How many SSD and HDD slots are available in Alienware 17 R5?

I have purchased an Alienware 17 R5 laptop. I was planning to buy additional SSD to install in my laptop. But I got conflicting information throughout the internet including Dell sale representative. I am completely take aback with this amount of confusion.

I have bought a laptop with “512GB PCIe M.2 Class 50 SSD + 1TB 7200RPM HDD”.

On checking the Alienware 17 R5 Specification document( https://topics-cdn.dell.com/pdf/alienware-17-r5_users-guide_en-us.pdf ) I confirmed to myself that there are 2 SSD slot, 1 HDD slot and 1 Intel Optane slot. Is this right???

Please help