Step 1:
Click on “Learners” in the title bar or on the home page.
Click on the pencil icon under "Action" for the relevant learner.
Step 2:
Click on "Play Settings".
Step 3:
Click on the down-turned arrow icon at "Extended Time" to expand the section.
Click on "Yes, enable Extended Timer".
To disable the Extended Time, follow steps 1 and 2 then click on "No, disable Extended Time".