After creating your new account, scribbl starts with a clean slate. Click 'Add scribbl..' to start adding your first scribbl.
You can now enter your first scribbl, and then click the save button.
After saving, use the "add tag" link on the right.
Enter a tag for your new scribbl. Then click the small save button.
And you're done entering your first scribbl.
The tag cloud shows your first tag. As you enter more scribbls and tags, the cloud will show a weighted overview of tags.
Interested? Don't hesitate to create an account.