How do I upload a sample file

I have a question which requires I post my working file for examination. But I don’t see an attach or upload button anywhere. How do I upload a file and attach it to a question?

To upload a file click the red-bordered icon while **edit**ing your question
image description

The answer is in the article linked from this site’s main page: How to use this Ask site.

Thank you for the answer. I was unable to upload a file before because it is apparently not possible to do this from an edit or comment (no icon is visible). The only way I was able to add a file to a previous post was to ‘answer’ my own question, which seems to work.

Please do not use Add Answer if you actually don’t answer a question but commenting an answer. Please use add a comment for that purpose. Thanks in advance …

I used the Add Answer section because it was the only way I could upload a file. Even the form for this comment does not allow me to upload a file. In my particular case, I made the original post without uploading the relevant file, so needed to do an upload after the fact.

In this instance, what other solution can you suggest?