Go to Settings > Wireless & networks > More… > Mobile networks > Access point names
Press the Menu > New APN
Enter name: Mobitel
APN: mobitel3g (For 4G LTE enter mobitel instead)
Proxy: 192.168.50.163
Port: 8080
Username: not set
Password: not set
Server: not set
MMSC: http://192.168.50.165
MMS Proxy: 192.168.50.163
MMS Port: 8080
MCC: 413
MNC: 01
Authentication type: None
APN type: not set