How do you perform a half halt?

again, my pony is 7 but has only been in work properly for a few years, and i am wanting to make his trot and canter more 'round' but he does not understand fully what a half halt is, can anybody help me to teach him?
thanks x

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…).