"Clear all caches" when something goes wrong

During the development of your site it might happen, that you can't see changes in your browser or that the site acts strangely. Frequently the problem can be very easily solved by clearing the cache. One key principle of Drupal is, that every site is built up dynamically upon request. To increase the performance, Drupal creates caches of your content so it doesn’t have to generate the same page all the time (reducing the amount of PHP processes and SQL queries being made). If you don't see recent changes in your browser or the site acts strangely, the reason might be, that the requested site is loaded from the cache. To load it new with the latest changes, you need to flush the cache. To do so go to Configuration > Development > Performance and press "Clear all caches"