using tag icons instead of tag text

It depends on the theme you are using. However you will generally find some code in your index.php file which says:

<?php the_tags() ?>

Essentially you need to locate where in your template file that its echoing out the text tags and replace it with the code you found on: https://www.ads-software.com/support/topic/show-tag-icons-instead-of-tag-text

You may want to also look in your theme folder to see if there is a content.php file which may also display show

<?php the_tags() ?>

where in your template file that its echoing out the text tags

I don’t know PHP enough to understand that, but do you mean I need to find
<?php the_tags() ?>
wherever it is, and replace it with the code from that other thread?

Yes. Essentially in one of your template files you should see the_tags() Note: there maybe some other code within the ( ), but you are looking for the_tags(‘possibly some code’)

Just replace the_tags() with that code and it should work.