Introducing myself and asking whether my planned first topic belongs anywhere

Welcome. The orientation materials are pinned at the top of this category and they take about an hour. They answer most of the questions a new member has and they save time in the longer run.

Practical note that does not fit anywhere else. Whatever you conclude from this topic, write down what you did and when. The single most useful thing in your own records is not any individual result; it is that they are dated and consecutive.

Introducing yourself is fine and requires no question. Post in this subcategory, describe the context that matters for why you are here, and lurk for a bit before posting technical questions. That order works well.

Trust levels accumulate over time and they give you access to small things like the ability to edit your own posts without a timestamp. They are not a status symbol and they do not make you more right. Someone at trust level zero with a good question gets better answers than someone at trust level four with a bad one.

On the reading order question specifically: start with the how-to-ask materials in this category, then read the one to three subcategories where your main questions live. The rest will be discoverable by tag once you understand the structure.