No result after running code in cells

I have nothing but problems with Jupyter Notebook, and it seems I am not alone in this.

I wish this course just used VSCode instead, no one makes production code in Jupyter Notebook anyway?

So the problem is, whenever I run the code in a cell, a block, the results disappear, it gets a * checkmark and turns blue. But I never get any output. There are no errors from Jupyter Notebook in my terminal window.

I attach two screenshots, before run and after run. The block collapses, no content shown.

Also, the videos, I am watching from 2019, the presenter has a run arrow, I don’t.