Using the Mission Model Canvas.

The MMC comprises nine sections ("Key Partners", "Key Activities", etc).

Editing

Click a section to begin editing it: a highlight will appear and you'll see a flashing caret where you can enter text.

Click outside a section or press Escape to stop editing.

Defocusing

Shift-click a section to defocus it (it will blend more into the background).

Type in any defocused area to automatically refocus it.

Reset

Ctrl+Escape opens a dialog that will allow you to remove all your text from the page.