The first step is to look if someone else already raised a similar question.
Use the search bar and type key-words about your topic.
After that, if you did not find any answer and you really need to submit your question, go to the forum page and click on the ASK A QUESTION button, or scroll. First, you have to select a category, then enter your title and add a description.
Choose the category which match the most with your question. If you don't know which category to use, select a main category (in uppercase) which match the most. As a title, you can choose key-words that would help to easily find the question topic from the search bar. Description is optional but is highly recommended to describe your question more precisely. You can also attach document if this can help other members to understand your question. Don't forget to check the “Notify me of follow” in order to receive notifications when any Spacewalkers has replied.