As you will notice after building your first Drupal site, there are frequently module updates published. The procedure for installing module updates is:
- Log in as user 1, or another account with permission to perform system updates.
- Put the site in maintenance mode, an option found from the toolbar, Configuration, Maintenance mode. This prevents visitors from affecting your database while you're performing the updates.
- Make a backup of your entire database and preferably also the file structure of your website. (You should at least backup the folder of the module you're updating.)
- Download the updated module and replace the relevant module folder.
- Visit update.php in the root folder of your site. There is a link available at the module list. The page will display a summary of the steps desribed above. Review these and then click continue to get a list of any update scripts that need to be run in order to convert old data in the database. Click apply pending updates to run them. (If no available updates are displayed, it means that you are already done!)
- Make sure that the website works as it should and then take it out of maintenance mode.
TIP: If you find the procedure above time-wasting, or even outright boring, you are recommended to check out the Drush project. This allows you to apply updates with a single command in a terminal.