Virtual Box Setup for Using Kali Linux

I've been working on setting up kali linux on virtualbox everything related to the setup is correct

But I need to configure kali linux to work over WAN , Because most of the exploits or attacks work on LAN ( My network ) , How is it possible to setup VirtualBox and kali linux to work over WAN , Also I'm aware that i should attempt portforward , but couldn't get it to work anyway.

I'm still learning and practicing so go easy on me

Thanks in advance

Respect :D