A good workflow helps you to get things done. In the case of TTG plug-ins, a good workflow helps you to get your website and images online with minimal fuss or trouble. Here are some tips to guide you along the proper path.
I am constantly writing and have previously written a great deal of documentation and tutorials relating to TTG web plugins, the Web module and Lightroom in general. And having written these things, I do want you to read them. But the best way to start with the Web module is just to dive in and play with the moving parts. Tweak the sliders, adjust the values, change the text input, and – just like a camera – click, click, click. Most of your changes can be observed on-screen via the preview. When you have questions or you're ready to upgrade your understanding, cross-reference the documentation.
The UI in TTG plugins is generally designed in workflow order. The best way to use the plugins – especially in the beginning – is to start at the top, in the Site Info control pane, and to work your way downward sequentially through the options.
When designing in the Web module, you will constantly be refreshing the preview to see your changes. The preview will render faster the fewer images you have active in the gallery. Work with a small collection of images, numbering five or ten, for the best response times while you design. And if you want renders to be faster still, work with JPEGs rather than RAW files. When the design is done and you're ready to publish, you can save a template and then bring in as many images as you like before exporting.
Or load your filmstrip with all of your images, but set the toolbar to Use: Selected Photos while you work with just a few selected images, then Use: All Filmstrip Photos to load the full collection before export.
The Upload button is tempting, but unreliable. For best results, Export your image galleries to the desktop, then use a proper FTP client to upload galleries to your web server.