PWA Commando, has standard stock..
 

I want to change my PWA Commando AR-15s fixed stock (M-16 standard style). I really know nothing about rifles as this is my first. I have been watching a lot of videos and from what I have gathered I will need a new buffer, buffer tube, spring, nut, receiver end plate and stock; would it be better to buy a complete kit like this http://www.brownells.com/rifle-parts/stock-forend-parts/buffer-tube-parts/buffer-tubes/dpms-mil-spec-carbine-buttstock-mounting-kit-prod27068.aspx

I would like a Magpul stock like this http://www.brownells.com/rifle-parts/stock-forend-parts/rifle-stocks/ar-15-m16-moe-buttstock-prod26706.aspx

Like I said, this is all NEW to me. I know I need some tools and a book might not be a bad idea either. My rifle is .223/.556. What do you all recommend?

It should be very straightforward, removing the carbine buffer will require a stock wrench, installation of the rifle buffer will probably require the wrench also, you won't at all need a book.

I would buy it all at once

That's a terrible price for a DPMS kit. And they may call it milspec but DPMS usually sells a commercial kit, which is what appears to be pictured there. If you can find anyone who has stock, try to get a milspec kit. PSA and BCM used to have much better kits for less money. PSA even had a kit with a MOE or CTR stock for not much more than that thing at Brownells. I know it's a bad time to be looking but don't settle on high priced junk.

As Sputnik said, a standard stock wrench will work on rifle and carbine receiver extensions.