This depends on the services you've signed up for, and your chosen start date.
You will notice that you cannot set a start date sooner than 15 days. This is purely to allow for the industry-wide set up time, which is an average of 15 days, though can be as much as 28 days. This is the day your initial services will be set up, and you will be billed at the beginning of the next month. There will also be different installation dates depending on the services you have requested, e.g. internet. You will be notified of these dates in advance, and will not be charged for anything beyond what you have used. We aim for all services to be installed as close to your start date as possible, though please note that there can be unavoidable delays during particularly busy periods.