Welcome JoJoSue
Large forums like this are organized by subject. There isn’t a "reply" button per se. But if you hit "quote" in the lower right, readers will know to which comment you are replying. If you just want to add a general comment to the topic, then write in the "reply to thread" box at bottom as you did already. That works too. More info on how to use this forum in the "TechnicalQuestions" section at bottom of this index page.
Go back to this page to see activity in the various topics and navigate between threads: http://forum.lowcarber.org/index.php? (First on the path above) From this page, if you want the Atkins forum, go here http://forum.lowcarber.org/forumdisplay.php?f=98. Or many use General Low Carb for Questions.
Also keep notifications on, and you will get an email Daily to any thread in which you have posted. If not, You can also tap on your own user name anytime to see All posts you have written.
Let us know how we can help, all the best,