Don't even dream of trying to do your first charter yourself unless you have plenty of time and budget to spare. It also inevitably screws up somehow.

I've sold charters to first time organisers before and can't remember a single one that went without a major hitch. The best ones probably wound up with 4 hour delays due to someone forgetting to do something, the worst one caused a major diplomatic incident with 80 people quarantined on a Barbados military base.

Airlines will quote a lower rate to a broker any day of the week simply because they know that there will be less effort needed for them to clean up the mess later.