Tour of the student learning experience on Udemy - 2019

[@Thebaguide]

You can also use the left and right arrow keys to jump forward and backward 5 seconds. I'd recommend you check out the other keyboard shortcuts available within the Settings menu (gear icon).

[@harrybomaye]

I cannot display the curriculum on the right of the screen anymore

[@henkes9469]

I had the exact same problem.
Try making your browser window a little wider.
(At least 540 pixels wide.)