What is the difference between pageviews and uniques pageviews?

Page views shows how many times the page has been viewed whereas Unique page view show how many different people/computers/devices have viewed the page.

Thank you, so what is the time period that these stats represent below (i.e., just today, forever)?

They represent from forever unless you have reset them or Google has reset them. If you have never intentionally reset them they are more than likely a "Forever" number. However, sometimes these are reset monthly to allow you to see the amount of traffic you get monthly.

I don't know how old the picture you posted is, but if its brand new then I would say those have not been reset as we are only 6 days into the month. I don't know what exactly you have posted, but unless you get mega traffic I don't see unique visits being that high this early in a month. Hopefully that makes sense.

I just posted yesterday, but the script it's on my website since long time.

How I can reset it. Could you please respond to my other question.

Please help me with this question.

https://www.experts-exchange.com/questions/28427144/how-many-times-this-page-has-been-visited.html

Do you have any tutorial on the dashboard link?