Build Help would be greatly appreciated

I am going through the resources on the side bar but I am completely new to this and don't have the slightest idea of how to actually build a pc or what I'll need to do it, I might get someone to build it for me or help me build it if I still don't understand after reading the guides.

I copied this build from another post by OneThousandOut. I want to get a simple starter gaming pc for my birthday/Christmas as all my friends have got PCs over the past few weeks and left me abandoned on console. ( I will be keeping the Xbox One, selling it for funds isn't an option ). I would like to run games such as rocket league, speed runners, fallout 4, csgo and Gmod as these are what my friends typically play together.

I don't particularly want insane graphics, 720p or 1080p would be fine with me. I'd rather be able to play most games on medium quality than a few n high quality. I'd like 60fps but will settle for 30fps as I'm not looking to go overboard with the price.

I'll have roughly 300-400 and not very likely but possibly 450 max 500 Euro (300-450 dollars). I live in Ireland, so the budget would have to accommodate shipping or the parts would have to be in Europe to reduce shipping costs. I just want to know the names of the parts and I will research price and delivery myself.

http://pcpartpicker.com/p/WFN2Jx Here is the start of my build. In the mentioned build, the author hasn't mentioned about a cpu cooler, optical drive, the OS, software or external storage. I'd really appreciate it if someone could tell me which of these I need to and should buy. Obviously they'll have to fit in the case and be powerful enough to do their tasks to a decent standard. I will research price and delivery.

I was also wondering what accessories I should buy with my PC. I have a turtle beach headset with a mic that I can use but what keyboard and mouse should I get? For any games I can sI will be using a controller so I don't want to go all out with the keyboard and mouse. I'd like a decent keyboard and mouse that will do fine for gaming but isn't going to be my priority.

If anyone has any good sites to buy parts from I'd appreciate the suggestions.

Thanks in advance and I really appreciate the help

Submitted by danielflynn2k12 Xbox 720 Release Date 2015