Software: Adobe Acrobat (Office)
User query: Sign 'GUICritic' in the 'Signature of Student'.
Difficulty: hard
Ground-truth plan:
Task 1: Navigate to the Signature Location
Subtask 1: Press 'Ctrl + 1' to resize the page to 100%
Subtask 2: Scroll through the document to position the area 'Signature of Student' (execatly the same Text should appears) in the screen.
Task 2: Add Your Signature
Subtask 1: Click on 'Fill & Sign' in the 'Tools' pane on the right side.
Subtask 2: Click on the 'Sign Yourself' icon in the Fill & Sign toolbar.
Subtask 3: Click on 'Add Signature' button.
Subtask 4: Type in 'GUICritic'.
Subtask 5: Click on the button 'Apply'.
Task 3: Place the Signature in the Document
Subtask 1: Navigate to the position of the signature on the screen. 
Subtask 2: Click at the position of 'Signature of Student' to place the signature.
Subtask 3: Click 'Close' to exit 'Fill & Sign'.