On the Mapping Definition of your import task, specify one or more IDs of projects to assign your tasks to instead of ["Enter your Project Id 1","Enter your Project Id 2",...]. The IDs should be specified as a JSON array: the whole list must be enclosed in Square brackets, the IDs must be enclosed in double quotation marks and separated with commas.
Specify the ID of your workspace to import tasks to instead of Enter your Workspace Id.
To create Asana tasks for specific new Zendesk tickets, configure filters in the task editor.
You can completely remove mapping for the Projects field if you don't want to assign the imported tasks to projects. Note that tasks are created as Private in this case.