This document will help you to establish wireless network connection without installing any programs and then, configure wicd that manages connections automatically.
List all net devices:
ip link
Activate the wireless one:
ip link set wlan0 up
Start wifi-menu and use it to configure profile:
wifi-menu wlan0
Now you should be connected to your network. Check that by pinging gateway.
Install wicd from repository (it may take a while if you hadn't updated your system before):
pacman -Syu wicd
Enable wicd service and reboot system:
systemctl enable wicd && reboot
Start wicd configurator:
wicd-curses
Choose your network and press Right arrow key. Check Automatically connect to this network and type your wifi key to key field. Then press F10 key. After pressing Enter you should acquire connection.
That's all.