I’m trying to have blocks of text that are all right of a given tab stop, like so:
However this doesn’t work, the first line is correctly indented but when the line wraps it goes back to the left edge of the document, when I want it to automatically start the next lines at the same position. I’m sure there’s a correct way to do it because it should be something quite common, I just can’t find what that is.
This is called outdent (the contrary of indent).
Create a style for these paragraphs. In the Indent & Spacing tab (Retraits & espacement in the French locale), set your margins Before/After for the paragraph body, mainly Before, aka. left margin. Give First Line (Première ligne) the negative value of Before. You’re done, no need to tweak tabs.
To use it: style your paragraph with the just created one. Type your “title”, then Tab which will align you to the paragraph left margin and continue typing as usual.
In case your title is wider than the “margin”, don’t worry. Type Tab after the “title” (as usual) then Shift+Enter. You’re now on the second line of the same paragraph at left margin.
Why type Tab after the title? This is to cause a “soft” break in text so that justification does not expand spaces in your title up to the right margin. You could, of course, disable this justification in Tools>Options>LO Writer>Compatibility (extend interword spaces on lines with manual newlines) but I find more convenient to keep it enabled so that I control individually which lines are justified and which are not.
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What you show is a table of two columns.
Oops! Not in this case, I think. 
Really? Playing with outdents, and applying character styles, just to achieve what is easily and consistently dine with table. Interesting what will happen with all the structure when the length of the defined word(s) will become longer.
You want a hanging indent paragraph:
Set up the paragraph Format > Paragraph > Indents & Spacing so that the “Before text” is set to clear the longest text string (in your screenshot, that would be “waveform_display_height”). This is a positive value. Now set “First line:” to that negative value:
Make sure your text has a tab between the “hanging” part, and the text that follows:
And that should do it. You can create a Style based on these settings if you’re going to use it often, then it’s easy to use it in future.
@dajare: there is no need to create a tab stop because the paragraph left margin implicitly defines a tab stop in the hanging case. Before I discovered this “implicitness”, I had trouble when tuning my margins to keep the tab in sync (remember tabs can’t be updated, only created/destroyed).
@ajlittoz Ha - so right you are! I’ll update my answer to reflect that. I guess we were typing at the same time.
