I'd look into getting cheaper parts, especially the cpu. Try this cpu: http://www.newegg.com/Product/Product.aspx?Item=N82E16819115037
Your professional got you the wrong type of ram for your motherboard. Not saying it won't work but there's a possibility. Unless said professional is going to overclock the motherboard and mess with timings I would try this ram instead: http://www.newegg.com/Product/Product.aspx?Item=N82E16820231226
Also your dvd drive isn't a dvd writer... Get something like this: http://www.newegg.com/Product/Product.aspx?Item=N82E16827106263
And you can get a much cheaper power supply that performs the same: http://www.newegg.com/Product/Product.aspx?Item=N82E16817339002
Once again, you can get a much cheaper case. Unless of course you prefer the crazy look of the one you got. Try shopping down this list and choose one to your liking: http://www.newegg.com/Product/ProductList.aspx?Submit=Property&Subcategory=7&Description=&Type=&N=2010090007&srchInDesc=&MinPrice=&MaxPrice=&PropertyCodeValue=548%3A8287&PropertyCodeValue=548%3A17804&PropertyCodeValue=548%3A8289
And one other thing you may want to consider is getting a sound card. Sometimes the sound coming out of the motherboard just simply sucks and if you get a sound card you will get slightly increased performance out of it. I recommend getting: http://www.newegg.com/Product/Product.aspx?Item=N82E16829102006 if you do decide to get one.
So if you follow my guidelines, I just saved you around $500-400 depending on whether you got the sound card I recommended. Everything else he recommended seems solid.
And as to comprehending where everything goes...
First you put the power supply and motherboard in the case. Then you put the cpu on the motherboard and put the arctic silver on the exposed side then put the cpu cooler on top of that. Everything else just connects to the motherboard like legos. Make sure your power supply is connected to your dvd drive and hard drive as well as the motherboard and your graphics card. You may have to connect it to the motherboard in 2 different spots.