Leave all other fields blank/not set (including Authentication type).
Make sure that data roaming is enabled.
Make sure that data is enabled.
If you configure these settings and they still don't work then please DOUBLE CHECK that you did not make any mistakes - e.g. some people have entered 48.months.liffeytelecom.com instead of 48months.liffeytelecom.com etc. The settings must be entered EXACTLY as specified above.
If you already have internet/APN settings but they are different to those above then reconfigure your settings so they match those above or delete any existing APNs and start again and add the 48 one anew.
If internet/data still does not work after configuring the settings correctly then try powering off and on again and maybe manually scanning for networks and connecting to 48.
If internet access still doesn't work then contact 48 support for assistance:
You need to check the documentation and user interface for your phone for specific instructions.
However, on most Android phones, the process is similar although there may be slight differences how to navigate the menu options to get to the right place and slight differences in the options that can be configured.
See here for an example of a general guide for Android phones:
If necessary Google for specific instructions for your phone.
A note about personal hotspot setup on iPhones
Once you have your internet APN set up and data/internet access working you can also use this connection as part of a personal hotspot (this will probably use up your data allowance more quickly than "normal" internet access so keep an eye on your quota and that you don't breach the fair usage limits).
This is generally straightforward on Android (and Windows?) but Apple sometimes make it more difficult on some iPhones/iOS versions for some reason...
Some people find that their iPhone / iOS 8 does not show the personal hotspot option in which case the following workaround may be required: