Trolley, I'm assuming from your post (it's not 100% clear) that you're logged in to the correct S&W Forum on Tapatalk. If not, do that.
You see the orange Tapatalk logo on the top left? Touch that: it'll open up a list of options for viewing. Explore those: you can view threads you've participated in, your messages, you can browse all the forums here. You go back by hitting that orange logo again (you'll see there's a "go back" arrow there). Explore and learn: it's faster than trying to review a Tapatalk tutorial here.
You want to post? Hit your phone's settings menu (that's the three lines if you're a real newbie with the phone) when you're in the topic where you want to post. Select "reply" from the menu that pops up (again, explore - there's a ton to do here) and your keyboard will pop up.
If you can't figure it out with your explorations, stay on your laptop and Google up the Tapatalk website and look at the FAQs there. It's a pretty instinctive platform, but - like anything - it takes you a minute to learn it. You'll be all over it in about five minutes, I'm certain.