There does not seem to be a simple way to create a new task and add to the top of Today's list - the "Doit now" section.
I have to add the item to Today, find it at the bottom of my Today list, then select the Doit now button.
In order to create a new to do and add it to the top of Today's list in one step, you could add the Doit now button to the new task entry box.

Thank you,

Julian