Samsung Galaxy S4 2G Network Settings

It is basic setting on samsung
SAMSUNG:
Nexus: Menu > Settings > Wireless & networks > Mobile networks > For 2G only, choose Use only 2G networks
Galaxy S i9000, Galaxy S II, Galaxy S III and Galaxy S IV: Menu > Settings > Mobile Networks > Network Mode > For 2G only, choose GSM
Galaxy Ace, Galaxy Mini: Menu > Settings > Wireless and Networks > Mobile Networks > For 2G only, choose the 2G Only Box