UNIX for Dummies Questions & Answers

Hi,guys.
Maybe you could help me a bit to become more flexible with unix...
I've installed on server CentOS,working on php script,that would send me emails and receive to my server and maybe a bit more later on.
I know how to copy,read,make files etc..i've learned file system a bit...i've even installed apache and php with tutorial
So i got to know a bit unix os,but the things that i miss is...
Like for example..on Windows,i've got Control Panel,to check what's on system installed,as i understood same is on etc directory in unix..is that correct?
Also what i don't understand is installment of new software,not compiling/making it etc(that i tryeid and everything is fine),but exactly installment,like for example:
Now how the hell can i come up with something like that? I should just sit around and there's the thought:"oh,right!i should install courier!here's how it's installed! yum ... " ?? I know i can download source or rpm,tar,gz etc,but i never seen on downloads such lines etc,how do ppl come up with this thing,how to understand it?
Another thing is like...I've tryied to install Postfix,finally i figured it out that i already have it So now comes the tricky part...configuration
Seems nothing too kinky,there's a lot of tutorials,there's a lot of documentation,but the thing is that when i open the document,i see a lot of stuff i don't even understand,i see it for the first time... Even reading the description doesn't make it clear enough...do i have to type in something?Or it isn't necessery and i can leave it blank?Like this:
alias_maps?db?virtual_mail?the mail that comes in or something else?their user id,login or what is it?it's just random config text,but there are far more complex,i think you know what i mean,but the question is...is there a way to understand it,besides finding some person who could sit near you and explain everything step by step?Because i tried Google and it gives kazillion links which are rarely relevant or i even don't undestand what the connection is...
So any advice on how to get more flexible with installment of new soft and configuration of it,on how to better understand what are you configing and what you don't need to change at all?

linuzx is not exactly unix. i wont say what i think is better, because im getting impaled here :P, but be aware that in linux, you have some apps that are not present in more arcane unix (like stat, date behaves weird, ect)
for now, try to get comfortable with gnu
that is not correct.
you can read this nifty link (directly linked to the etc part)
/etc
here is the full version
Linux Filesystem Hierarchy

again, beware that older unixes might be different
welcome to the wonders of automated package management
this is a linux feature
yum will read the config files in /etc/ymu.conf, and /etc/yum.repos.d/ and collect a series of urls (might be ftp, or http).
from those internet sites (calles repositories) yum will download a list of available apps (simple text file that has the name and version and some other stuff).
in your example, you say "yum install courier-base"
yum will read the list of available apps.
if the text you gave it, is the exact name of an package, then it will simple dowload the rpm (red hat package) from the said repository, unpack it, execute any posible pre-install script, copy all the files where they belong, and run any post-install script. simple as that.
if you want to install a package that needs other packages to be installed previously, yum will realize that, check if they need to be installed (you might have them already), and add them to the download queue

and how in earth someone came up with the name ? well, simple

Code:

yum search <some text that might be name of the app, or description>

Code:

yum list <name of the app, you can use wildcards like *fire*>

i suggest you read the manpage of yum, it has more neat options like, "yum provides libstdc++.6.so" and it will tell you which package has that file

part of the automated package management. the packages comes with the app and its configs.
some times, the default works fine (for example for example sshd)
some times it works fine, but is most certain that you will need to change it (like apache, who comes with a etst page configd, and you need to add your own, but you dont need to config EVERY thing, like ports or log files)
or some tiimes, it comes configeured to suit system nneds, which are most certanly not waht you want, for example, postfix. in that case, it comes preconfigured to suit the internal mailing. some programs like logwatch, use them to mail the root user some status files of hd usage, or similar

this is to much specific for me, i never touched postfix, but if i where you i would read the config file, and when i found an option i dont know, i would read in this order
man page
oficial faq or documentation
google the exact config option, along with postfix config
sorry i cant point you to a good document, never had the oportunity to work it myself
the best way is to simple try and break it
and learn from the mistakes, and the hard work spend in fixing it