different pages – different formats?

Check out Custom Page Templates. You’ll create secondary files, such as page-sidebar.php, with the coding you’d like. When you publish a page and there are additional templates available, you can select a Page template from a dropdown in the editor.

how can I have different setups on different pages.

By using a combination of different template and CSS. See Theme_Development.

Do I need to have different themes on different pages?

No – you can only have 1 theme active on a site at a time.

I’m not clear on how to use code building my site. My background is a coder and this is the first time I’ve tried using a “cookie cutter” site, so once I get clear on how to do it, I should be fine.

So starting from the beginning, when it says to create a filesuch as “snarfer.php” – where does this file live?

In your theme’s folder.

But I thought I could only have one them active on a site

Correct. Are you confusing themes with templates? A theme is made up of a number of templates that all live in the theme’s folder within wp-content/themes. You might find Theme_Development useful.

I was looking at that. I got to the part about creating a file for a custom template and this is where I don’t understand. How am I creating this file and where is it supposed to live?

How am I creating this file

In a plain text editor.

where is it supposed to live?

In your theme’s folder within wp-content/themes.

I see. Does it live inside the theme folder of my active theme?

Yes!

And then – how do you look you call it up as a template for a page?

Using the Page Template dropdown in Add New/Edit Page.

I’m not getting that dropdown. the only dropdown I get is a parenting one (which I have to admit, I don’t understand the parenting paradigm either). I’m using the foghorn 0.3 template. Could this be a limitation?