How do you install software off the internet using the linux operating system?

Hey,

Im trying to install avast for linux but im having no luck what so ever. When i download it in firefox it comes up with the usual box but when i double click on it, it says i have to open it with something? What do I have to open it with to make it download? any ideas?

Thanks.

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia…).