If you have a Trello Business Class account, you will find the option to export all cards on a board via csv from the board settings menu. If you are not on this Business Class plan, then you make use of this third party chrome add-on to export your Trello data to a csv file.
Once you export all your data as a CSV, you can now import them into your freshrelease project. If you are the project admin or the account admin,
1. Go to your project
2. Go to All items tab
3. Click on Import > Upload the .csv file from Trello
4. Map item fields in Freshrelease > Import
Once your data has been imported, you will get a email confirmation.
Important points:
1. While importing items from Trello, if the records have user emails in assignee or reporter field, Freshrelease will automatically create the users if they are not present in Freshrelease.
2. If user name is given in .csv for Assignee and Reporter fields, freshrelease will try to match existing users with the name in .csv. If there's no match, the item won't be created.
3. If you want to automatically create missing Assignees and Reporters, then replace user names with user emails in the .csv file.