One way to find an article is by going through the Main Menu. On Joomla, go to Menus -> Main Menu item:
This will show a list of main menu items. You can search for the article you are looking for by clicking on the search bar, or going through the list to look for where you are.
Click on the menu item, or select it then click on Edit next to the green New button.
Make sure what you selected is an article by looking for 'Select Article', and make sure this is the article you are looking for by checking it's name next to the Edit button. Next, click on the Edit button.
You are now able to edit your article. Once you're done editing, hit 'Save and Close'.