how to configure network during the setup and Crashes

[avid.runner9]

I'm trying to find ways to configure network, but i'm not getting how to do that.
its getting 2 option :
eth0
wlan0

when i clicked to wlan0, it ask me some key dont know what, so i entered my wi-fi passwd but not working
when i clicked to eth0, it automatically does something (IPv4, DNS etc) and this too not working.

so i always have to click 'configure network latr' and had to skip 'network mirror'.

and once finish installing i have another problem

after start i use apt-get update
apt-get upgrade
apt-get dist-upgrade to make system uptodate
and always it ends crashing the system
previous it was due to postgresql then ruby-zip then something the other.

i dont know y, please somebody help. right know my system has in crash mode so i have to use live.
please respond, urr feedback will be appreciated. Thank You

[muts]

This is a useless request for help. What does "when i clicked to eth0, it automatically does something (IPv4, DNS etc) and this too not working" mean ? If you want people reading these forums to make an effort to help you and solve your problem, you should also make an effort in making your problem as clear as possible for others.