How to write Markdown
ImpressKit uses Markdown editors for the text overviews of press kits and press releases. I choose this format because it is reasonably known (for example, GitHub uses it for project readme files). It is constrained, which helps to keep sizes and other elements within reasonable bounds.
I realize that not everyone is comfortable with Markdown. That is why ImpressKit uses SimpleMDE Markdown Editor, which offers a handy toolbar to access all the styling without knowing the rules. You also get an inline preview of the formatting.
Below I have collected a few tutorials that are free and can help you get started.
Guide on MarkdownGuide.org for the basic syntax is quite lovely, although it complicates things a bit since it shows alternative ways to achieve given results. I try to stick to the most popular syntaxes, so my text is compatible with various editors and websites.
If you prefer video, Wes Bos has an excellent free course on Markdown over at MasteringMarkdown. The whole course is 34 minutes of videos, but you can safely skip the advanced later lessons.
Another free video tutorial is this one from Faraday Academy on YouTube. It is also around 30 minutes long and has chapter markings.