How do I actually use this to fetch a matchID?

[mattnotmitt]

Could you show me an example of how to fetch the ID?

[andrewda]

You should listen for the newGame event.

var Live = require('hltv-live-games');
var live = new Live();

live.on('newGame', function(data) {
    console.log(data);
});

Not at my computer right now, but that should be all you need.

[mattnotmitt]

thanks :D