How to Port Forward Usin 3g-Wifi Router ?

Hello friends,

I am using TL-MR 3420 3G/4G Wireless N Router + Huawei E3531 3g dongle for connect internet ,

My 3G connection ISP is Dialog Axiata,

May i know please,

how to port forwarding using TL-MR 3420 3G/4G Wireless N Router + Huawei E3531 3g dongle ?

1) am i should change my local ip to static ip and how i do it correctly ?

2) what is the best dns server for port forwarding ?

3) should i turn off my anti virus guard when i port forwarding ? (eset smart security 8)

If any one can give me a description,,tutorial,screen short or any valuable link it's very appreciate, thanks you !