Hi! Here are the steps that you need to follow in order to publish your question:
1. Click on Explore
2. On the left, you would notice the various topics under the header 'Related Topics.
3. Choose the topic in which you intend to post your question.
4. You can keep choosing the sub-topic, till you get your precise section for posting a question.
5. Once you have finalized on the topic, scroll down on the left till you see the section called 'Questions & Answers'.
6. Click on 'All Questions' located at the end of this section.
7. In the corresponding displayed page, you find a box on the top-right, where in you can type your question and post it using the 'Ask' button.
Hope this helps:)