Think I just (finally) found out how to click the check icon. A bit confusing however, since you repeatedly write in instruction that the check icon is GREEN. For me, it gets green when ticked.
The main thing is that you now know what you've got to do but the check mark was not supposed to represent the button you need to click, just a check mark.
ie. supposing it was a thumbs up button I would've said which doesn't necessarily mean it is what it looks like, it's representing thumbs up.