You can activate your trial from any Trello board after installing Elegantt or by downloading the new update.
The PRO account is per team. All the PRO features are automatically available on all the boards of the team you chose when you registered for the trial.
Elegantt PRO is available for the Trello Team you chose which means you'll be able to use Elegantt PRO on that same team's boards. If a Trello Board is not from the Team you registered to Elegantt PRO with, then you will have the free Elegantt version.
Activate your trial
You'll see on the Elegantt menu of your board a notification 'Activate your trial':
By clicking on it, you'll be redirected to elegantt.com to activate and create your Elegantt account:
To select your Trello Team, you have to Trello login. Elegantt PRO is available for the Trello Team you chose which means you'll be able to use Elegantt PRO on that same team's boards.
If you haven't a Trello Team, you have to create a Trello team to activate the Trial or Elegantt PRO.
If the notification 'Activate your trial' doesn't appear:
You have to grant Elegantt permission on the board you're in
Someone from your Trello Team has already activated your Trial so your trial automatically started as well
You already used your Trial and you're back to the free version of Elegantt :)