Choose a To Do list

When you first use Tasklist with To Do, Tasklist will ask you to select a To Do list to use.  You can select a different list for each task, but Tasklist needs a list to start with. You select a list by clicking on the Preferences button in the To Do tab of the ribbon:

This will bring up a dialog that lists your To Do lists.  You can select a list, or you can make a new one by clicking the Make a New To Do list button:

Click on the list you want to use, and click OK.