Need Help Understanding Internals.

So I have my L96 and reading around the forums and with help from many of the members I no know my gun inside and out. I have recently been looking into gas and I was planning on getting a m700. Not Tanaka, but a clone. The only problem is that I have never owned or used a gas rifle, so I do not know any of the internals. I want to learn more about the internals of a gas rifle, so I am going to link some products off of AGI and if anyone could explain what they do for the gun, that would be amazing.

http://www.airsoftgi.com/product_info.php?cPath=362_365&products_id=6427
These pieces, from what I read, go into the back of your bolt. They strike the part on your magazine releasing some gas to shoot the BB. Does this increase the consistency of the gas usage of the magazine?

http://www.airsoftgi.com/product_info.php?cPath=362_365&products_id=6433
I am assuming that these help keep the flow of gas in the gun and prevent leaking of some sort. But you know what they say about when you assume.

http://www.airsoftgi.com/product_info.php?cPath=362_365&products_id=6432
I have no idea what this is at all. What does it do?

Those products are what I have no idea about, except for the first one. Most of the other ones on AGI I can sort of guess where they go. Any help on the internals of the M700 would be amazing.

Thanks
Sniper