Fibre connectors and how to connect to Ethernet switch

Hi,

I've never dealt with Fibre connections before. We're moving to a new office (2 stories Bldg). The 1st floor will have the current Production System (Ethernet connections / switches). In the ground floor we will create a backup system(most probably Ethernet connections / switches).

ATM they're running 12 Core Multi Mode Fibre Cables between both systems locations, they're about 45 - 50 Meters apart.

I'm planning to buy DELL 5524 Gigabit Switches with dual 10 Gbps fiber uplinks (SFP+).

DELL website Link: http://www.dell.com/au/business/p/powerconnect-5500-series/pd?~ck=anav

Are these switches suffice to connect both systems via fibre cables?

How many Fibre cores do i need to terminate ?

What type of connectors should i use to terminate those cables?

What is the future benefit of having a 12 Core Multi Mode Fibre Cable?

Your advice and recommendations is much appreciated.

Thank you