where is the answer to my questions

You can use the My Discussions button in the Quick Links section of this page.

You can also do a search with the magnifying glass tool at the top of this page. Then you can use the Author filter on the resulting list, specifying your user name, to limit the results.

You can also look in your profile activity at https://community.familysearch.org/en/profile/activity/ which has two links, Posts and Comments, which you can use to find your discussions and comments.