SEO for website UR

I understand some precautions must be taken with regards to URLs for SEO. On my website, I have a 301 redirect from to as I understand that otherwise this can duplicate the webpages.

Is there a difference between and ? Do I need to have a redirect somewhere to ensure they are the same ?

If, for example, I want the URL of each webpage to end with / I can do so by naming each page index.html and placing it in a folder of the desired name, such as the about page would be Is there a difference between this URL, which is my preference, and, which both lead to the same file ?

I also think this may not be a good method to achieve this, is there an alternative which is good for SEO and will allow the URL of pages to appear as above.