The club never said what the requirements actually were though, just that you had to have applied for additional matches.
The ballots will be rotational ballots. This means that every supporter will receive a ticket within your tier before you are eligible to receive another ticket.
For certain high demand matches (such as Aberdeen, Celtic, Hearts and Hibs), supporters will be required to have registered for additional matches before these games are available to apply for. The match application threshold for these games will be communicated in due course.