I'm new to Drupal and PHP. I've found many answers on stackexchange to the question of bulk adding fields to existing nodes. I need to add a field, like a tag or date (for future facet filtering), to existing nodes. I've been successful with creating a content type and setting up the default fields for users, but now we'd like to figure out how to do this if the nodes have already been created. The VBO module may be the best answer, however, we may have a few hundred of these nodes.
I see plenty of great example code, however, I am unsure of where to use this code. Do I do this on phpmyadmin? I'm more familiar with SQL, but I've read advice here that SQL should only be used if very familiar with Drupal. I'm using Drupal 7.