In Tkinter I'm trying to make it so when a command is run a widget is automatically selected, so that a one may bind events to the newly selected widget. 
Basically I want it so when I press a button a text widget appears. When it appears normally one would have to click the text widget to facilitate the running of events bound to the text widget. I want that behavior to automatically happen when the user clicks the button. So that one does not have to click the button and then the text widget, but simply the button.  
I'd also like it so if one started typing after the button was pressed it would automatically start filling the text widget. Again to cut out having to click on the text widget. 
What bit of code does the above?
The terminology which describes what you want is "focus" -- you want to set the keyboard focus to your text widget. To do that you need to use the focus_set() and/or focus_force() methods on the text widget.
Selecting Widgets