Could more guidance be provided on how to setup the environment and run the javascript examples in chapter 2?

I tried doing this on Ubuntu and could run simple java scripts but when I attempted this example I couldn't make it work.
Not sure how I am suppose to organise my comments.I think I will post by chapters so not too many threads are created.

I have tried the quiz at the end of the chapter and I don't seem to get results for some of them. Are you able to outline how many elements should be returned for each answer.
For example for solution 2 div.wrapper... I can't get anything back.

I am using jQuery3ESourceCode(1)/chapter-2/lab.selectors.html I hope that's write.
I like the examples about using Never seen it before, it seems to help experiment with things, although I do not know how to use it fully.
For the example of p49 about the levels I am not sure what I am suppose to do with it though when I get to the linked page.
Am I suppose to type some command in the console to do various queries. I tried but had no luck. I notice I keep get back the value of 2. Not sure what that is about.
Perhaps a few examples of how to get results could help the reader get more about this example posted on jsbin.
Actually I worked some of it out now. Yeah I am a beginner.

I can see now that I can experiment with the line
var $elements = $(".levels li:pointsHigherThan(50)");
By changing the 50 to 5 I can get a count of 3.

What command would the reader do to type out each line to the console so that the reader sees the actual values retrieved instead of the count as I think that could be more interesting? I suppose I am asking how do I see what is inside $elements as that would be rather interesting instead of just a count?
Reading page 25 about using a console or debugger to viewing the variable $allElements to see what DOM info was selected. It would be useful to explain how to do this using a console in a browser. I haven't learn't how to yet. I think those type of skills would be useful in learning more about the DOM and debugging and working with jquery.