# Set up ### Authentication You might choose to create a specific integration user that can be controlled by a trusted member of your business. This mitigates against the situation where you have to delete a user that Avion is authenticated with if a person leaves your business. [More info](https://help.avion.io/docs/integrations/set-up-an-integration/authentication#create-a-dedicated-avion-user). {% hint style="info" %} You might need to allow pop-ups if you browser blocks them, as Avion uses a pop-up window to authenticate with Trello. {% endhint %}

Don't forget to scroll down, as this screen can be quite long 🙃

### Board selection

### Backbone and sizes sync selection

If you would like to keep this data in sync you will need to enable **Custom Fields**. Be aware that this is a now a paid feature of Trello:

{% hint style="info" %} Once the integration setup is complete, you can stop these fields from showing on the front of your Trello cards, or even rename the custom field, if you wish. Please note that **if you delete the custom field, that data will no longer be synced**. {% endhint %} ### State mapping Map your Avion [workflow](https://help.avion.io/docs/story-map/workflow) to your Trello states. [Advice and info](https://help.avion.io/docs/integrations/backlog-tools/set-up-an-integration/map-story-states).

### Import from Trello Import your backlog from Trello. [Advice and info](https://help.avion.io/docs/integrations/backlog-tools/sync-data/importing).