Topic's, sometimes called 'threads', are easy to reply to, all you need do is just follow these steps:
Replying to a topic or poll is basically the same as starting a new topic, but it's not necessary to enter anything in the Subject field unless you wish to change what's already there.
As shown in the picture below you can click on reply, found at the top and the bottom of the thread, or...
Click on Quote to have a copy of the selected message display within your message.
example: if a thread has 5 replys to the original post (for a total of 6 entries to the thread) and you want to make sure that everyone knows that you are replying to the message posted in reply #3... then simply click on the quote button in reply #3 and that message will display in your post.-----------
If 'Quick Reply' has been enabled, a simple reply field will also appear after the post(s) on a page, but you'll have to type your Bulletin Board Code and Smileys manually if you choose to use it.
Simple Machines - SMF User Help: PostingIf you would like to see the Basic Posting page written by the same folks that wrote our FamilyForum software just go to the link above.
It is a well written and highly informative How-To on many of the features available here on the forum.
* Much of the info for the tip above were found on those SMF pages.