I was told to check out the documentation which did not answer my question I originally asked.
If I wanted to change the css tags and div references could I? or will I encounter problems with your software?
As it has been already answered, if you copy wpForo template files to /wpforo/ folder in your active theme, then you'll not have any problem.
You can insert custom css code in wpForo > Settings > Colors & Styles admin page
I meant the tags that are already in the plugin like #wpforo. I want to change those. Can they be changed if I changed those and the div references?
I have another question about the documentation using custom templates.
Is there any chance of changing this: wp-content/themes/yourtheme/wpforo/layouts/1/topics.php
to something like this: wp-content/themes/yourtheme/boards/layouts/1/topics.php
Without encountering any problems?