Need some Double chekcing and some help with everything

[Wateraj]

Hi, so recently anxiety has overcome me a bit and I just have a few questions and would like some help

For some context this is my first server kind of build, I've built gaming computers before. I will mainly be using the server to hold my ripped movies and shows for Plex. Price is not a problem just trying to keep it everything realistic. 

My part-list so far is

CPU: i5-7400

MOBO: Need help finding one that would be good for plenty of sata ports. Right now I have a cheap HP one, the board only has 3 sata connectors. 

PSU: I have a old Thermaltake W0319RU 850w with no sata power cables, I was also considering picking up EVGA BQ-0500-k1 Bronze Semi Modular.

Case: Antec Three Hundred Two 

Storage: Plan on buying 2 twelves, one for parity, another 10. I already have one 10 and 2 8s, WD and Segate Externals that I will need to transfer. A Kingston 120gb for cache. 

Ram: I have two 4gb ddr4 2400 Hp Ram.

Other: Shine star Sata Card 4 Port, 4x Sata Power Splitter, just a tiny thing of thermal paste. 

 

Questions

• Am I missing anything / can you help me find some reasonably priced
• Can someone explain the process of transferring from external drive to internal
  • If I understand correctly, since I going to be adding 22tb with nothing on them, I can move over the two 8s shuck them clear them add them to the array. Then copy over the 10 shuck, clear, and add to the array.
• Is there any extra tips I should know