There are several ways to import a tracker, its fields and its data:
In the Edit Fields page (/tiki-admin_tracker_fields.php?trackerId=) you need to select all fields you want to export with the checkboxes, then at the bottom there is a dropdown where you select Export Selected.
This will open a window with the code you need to copy, then paste in to the Import Tracker Fields tab.
To import data, you can import data through the other interface:
In order to get the right syntax for the file, you can export your tracker data first, so that you can see an example of how columns are data are formatted. See Export Trackers.