Newbie to XML publishing. What role does XML, DTD, Stylesheets

One more thought. If you are working with an external translation vendor, there isn't much point guessing what to do. They are likely to have very rigorous requirents for what they receive from you, and if it's XML I'd expect that THEY have a mandatory DTD and predefined workflow. It's nice to practice with the tools, but don't put too much into the detail at this stage.

I'm new to XML publishing and want to support a simple workflow for translation. Goal is to...

Format an existing InDesign file using tags and stylesheets, export XML-->translation vendor-->import new translation in file (using exact same structure and formating of master language file). I have a few questions:

I do, too. Why do you want to do it this way? 

No, but seriously. I will totally take a stab at answering your questions, but first, I want to know why you've started with such a complex translation workflow. InDesign can export a file of the type "IDML" which is a markup language rendering of an InDesign document. It successfully captures everything but placed images, and I think pretty much every CAT tool and TMS in existence can consume and generate IDML. There must be exceptions, but I can't think of them at the moment. So, you're starting your translation process in a place where you seem to be doing way more heavy lifting than is necessary. Why have you skipped IDML and gone straight to XML export/reimport? 

Do I need to have to a DTD if my paragraph styles match the tag name?

Nope. 

Does this mean I must use one connected text box, or can there be multiple containers.

There can be as many text frames as you like, so long as you tag 'em all in the Structure panel. In fact, one set of threaded text frames - one "story" - winds up getting a single tag. Stuff inside those threaded text frames (e.g. paragraph styles that you've mapped to tags) appear under the tagged frame in the Structure panel. 

Following some other guidance video I found online, I have no cloned styles/tags.

That's good advice for an XML translation workflow in InDesign... can you post a link to the video? 

It fact, the XML can be imported into a field based content tool (ultimately the goal).

So, what's the goal again? You have English-language content in an InDesign file, and at the end you don't want a non-EN InDesign file? It's just a step on the way to your goal of content management? I'm not completely sure what your field-based content tool is, in this context, but if your main goal is to get all of your content into it, I can offer you some suggestions. If you're going to be using a language service provider of some kind (that's the "tranlsation vendor" in your post), then it should be Extremely Easy to get them to deliver your translated content in a way that makes it very easy to hoover up into your content management tool, which is what I am guessing your field-based content tool is. 

Said another way: if you have content in English, and you want it in a lot of languages, and your English content isn't already 100% in InDesign documents that are already well tagged and ready for XML export, then there is approximately a 99.44% chance that there is a better way to get your content management tool full of translated content. 

I could be wrong! Maybe, after you explained your workflow to me, I would respond, "... aw, jeez! You're right, the fastest & least error-prone way for you to do this is to house your English content in InDesign, and tag it up there, and export XML for your LSP." But I really doubt it. If it needs to be in XML, there are better places to work than InDesign, and if it needs to be in InDesign, there are better ways to translate it than exporting XML. Usually. 

As InDesign does very little with XML, I think you must have meant to place this in the FrameMaker forum, which is very much an XML/DTD-driven app. In any case, you will get much more useful answers there, I think.

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