I can not believe this. We got GIGABIT Internet!!

It feels like a freaking dream.!!!

NewLifeNewHope update No.2 / Day 5

My Server Is finally opened and i installed 2x8 TB WDC Harddrives and SATA 128 SSD. I know this server is freaking garbage, but i got this PC for free, and have somewhat good-ish upgrade path, so heres the spec :
-Gigabyte H110m-S2 LGA1151
-Intel i3-6300
-8GB DDR4 single channel RAM
-128 GB SSD
-2x8TB Harddrives
-TP-Link 1000mbps NIC

so the plan is to make this server as the Main Repository -- yes no offsite backup plan for now -- and also i want to make this server as an Email Server and for hosting my company's website. I've already asked for static IP from my ISP and will take effect tommorow.

I need help for choosing the Operating System (i like centOS) for my server. and to setting this Server to work like what i planned but i don't know where to start, Any help and/or References will be great !