There are multiple ways to edit/view a task. Go to the folders tree view and select the folder where the task is located. All the tasks for this folder will be displayed on the list situated on the right side of the folders tree.
Then you can do the following:
1. Double click the task that you want to edit/view.
or,
2. Right click on the task that you want to edit and choose the Edit option from the displayed popup menu.
or,
3. Click on the task that you want to edit/view and then click the Edit button on the toolbar (this is the second button on the toolbar)
or,
4. Click on the task that you want to edit/view and then go to the File menu and choose the Open Item option.
or,
5. Click on the task that you want to edit/view and then go to the Tasks menu and choose the Edit option.
The selected task will be displayed in a new window and you can edit/view it.

If the task is completed and you have set the "Automatically Move Completed Tasks to Completed Tasks Folder" in the Preferences window, then the task will be automatically moved to Completed Tasks located folder under the Tasks folder.

If the user sets task's due date, then an event will be automatically created in the folder Tasks Due Dates under the Calendar folder.