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Having the buttons in the four corners in the working through the steps screen is efficient due to Fitt's Law. Having autocomplete when searching through patterns and tutorials would also increase efficiency. Because it would be inefficient to go through all of the steps of the project one by one to find where you left off, it is important to have the screen which shows are steps and you can click to any one of them to get to there, as well as the resume project option in the active projects screen.
Safety:
The flashing warning button in the working through steps screen is there to help the user sew more safely. The alert button should be bright red and flash briefly to remind the user to check, so that they have a reminder to help avoid disastrous and annoying mistakes. It does not pop up automatically, because that would reduce efficiency and cause the user to perhaps automatically ignore the alert. Outside of this, there is not much safety in this design. Part of this is because the user does not make any changes to this thing itself other than navigation, which can be easily undone. However, the user should be able to modify their active projects screen by deleting a project. In order to make this more safe, a single-level undo should be added.