Before you draw
Check the entrant count and, if you used required actions, the eligible count — they're different numbers. Anyone who skipped a required action is excluded no matter how many tickets they have.
You don't have to wait for the campaign to end, but entrants generally expect you to.
Running it
Dashboard → your campaign → Draw winners. A random seed is generated and committed to the campaign row, then each winner is derived from HMAC(seed, index), weighted by ticket count, with no repeats.
To pick specific winners yourself, switch on manual mode and select them from the entrant table. Any slots you don't fill are drawn randomly from everyone else.
Proving it was fair
After the draw, the seed is published on the campaign. Anyone with the seed and the entrant list can replay the exact same result. That's the whole point — publish both and the draw stops being something people have to take your word for.
Afterwards
Winners with an email address are notified automatically. If the campaign is set to require shipping, that email includes a link to the address form.
Re-drawing is possible but deliberately awkward: you have to confirm it, and if the new draw fails to save, the previous winners are restored rather than lost.