If it works like previous ones, then they'll sell a maximum of 250 take a number tickets. Of those, up to 150 will be allowed to talk to Frontier. You don't buy individual take a number tickets for each airline. You just buy a take a number ticket, and specify which airlines you wish to talk to. The first 150 people that list frontier as one of the airlines they wish to speak to on their take a number will get to talk to them.

At least that's how I remember it working when I went.