To import your existing projects and tasks from Asana, first go to the MeisterTask dashboard and click the (+) button at the top of the project list. Select Import from Asana... from the menu.
You will then be prompted to select an Asana CSV file for import. That's it! Now you can continue working on your projects right in MeisterTask.
Note: attached you will find a .csv example of how the file should look like. If the format is respected as the one from the file you can also add your own tasks to import them directly.