I assume your using explorer Dewdrop? The arrow key on the left doesn't close the webpage, it brings you back to the previous page you were on. You should see a small "X" at the right of the webpage, and click on that to close a page. If you have several "tabs" ( or web pages) open at the same time, you can close them individually doing this.
PS to go to your homepage, click or the small house symbol or the right of the tab.