The voicemail service on your new SIM card should already be configured so it can be used immediately. Here are some short cuts you may find useful:
Turn on standard Voicemail – call 1211
Turn off standard Voicemail – call 1210
To divert all calls to Voicemail so your phone doesn’t ring – call 1212
To cancel call divert to Voicemail – call 1213
Use the Voicemail menu to change these settings by dialling 121