do you guys know how to turn on the light at the the top left of the squares? [closed]

here's the video of it https://1drv.ms/v/s!AuNT_JgXUNfdjRlICHnAqKOxQG-2. the start point is at the top left of the squares. I've been tried to code lightOn(); at the beginning of my code, but it didn't change. Then I tried to code it to turn and go up to return to the start point and light it up, but seems like something block the way to the start point.