Thanks very much for the reply. That works fine if I click into a specific post. But clicking on the category in the menu heading (which is a category page that returns a blog stream for that category) won’t bring in the custom sidebar until I click on a specific post.
This is the first time I have created a website and I’m having fun learning how to use the tools. I think this is my problem fundamentally – I want to create a blog which, at a high level, will contain two different subjects. So I would like to have a custom sidebar for each. And the sidebar that appears would depend on which pages, categories, or posts the user clicks on as they navigate the site.