First of all you need to know what is your wireless interface. Use the command ip link to find it out. Wireless interfaces start with wl. The command ip link | grep wl should list all your interfaces. Use the command ip link | grep wl | perl -n -e '/^\d:\s+(.*):/ && print $1' to extract the name of your wireless interface. You need to make sure that you're connected to your interface by running the command sudo ip link set interface_name up.
After this you need to make sure that the netctl tool is installed. As this tool is part of the base group, it should already be installed in your system. After this we need to create a new profile in the folder /etc/netctl/. Create a new file in this folder named eduroam or whatever you want.
Copy these lines to that file:
Connection='wireless'
Interface='YOUR_INTERFACE'
Security='wpa-configsection'
Description="eduroam network"
IP='dhcp'
TimeoutWPA=30
WPAConfigSection=(
'ssid="eduroam"'
'key_mgmt=WPA-EAP'
'eap=TTLS'
'proto=WPA2'
'phase2="auth=PAP"'
'anonymous_identity="YOUR_IDENTITY"'
'identity="YOUR_IDENTITY"'
'password="YOUR_PASSWORD"'
)
After this we're almost done, just start that profile by running sudo netctl start NAME_OF_YOUR_PROFILE