The quoted instructions proceed on the assumption your phone is already configured.
According to
this page you just need to create a new data profile in your phone with "internet" as APN:
Here you are:
1.Set Access Point
Settings-> Connectivity-> Access points-> Add Access point
Connection title: (name it something, e.g. "O2 CZ")
Bearer: GPRS
Authentication: PAP
Username: [leave empty]
Password: [leave empty]
APN: internet
[Save]
2.Internet profiles
Settings-> Connectivity-> Internet profiles-> Add Profile
Title: (name it something different than above)
Use proxy: OFF
Access point: Select access point previously created ("O2 CZ")
[Save]