I think it will take me a while to learn how to navigate and use this forum. I am especially confused how to post a reply without creating a new topic. I didn't mean to do that, sorry.
all I can think of, Mayfield, is to use the web version (switch top right, in the menu). That should give you the buttons for edit and reply. And read the start page with Downton's hints!
other than that, we are all still learning, lol - different forum provider. Some things are better, and some things we haven't found yet
As DD asks, are you using the web version Mayfield? If not you will find the layout much easier if you switch to it. The mobile layout needs work.
In the web version, which you can switch to by clicking the black box with white lines in the top right beside the search icon. You can just start writing your reply in the white box at the bottom of the topic you are reading