Open the Google Chrome developer mode(F12) and click "Sources" tab.
At the left side, you will find some HTML files.
Select the HTML file to debug. If the source code is invisible, refresh the page(F5).
When you click a line number, It is checked. It is called the breakpoint. The breakpoint is recorded right side's "Breakpoints" list.
When refreshing the page, the breakpoint will work.
But if you don't want to debug anymore, click the resume button(F8).
If you want to run a line of source code, click the step over button.
If you want to go into a function, click the step into button.
If you want to exit a function, click the step out button.
※ I personally don't recommend you the step button(→). Because this runs every single source, debugging can be disturbed by moving to an unintended location. So I will not introduce it here.