You can also write a new post out in the standard box at the bottom, including a quote if you want; hit the Edit button on your last post, then cut and paste the contents of the new post into your last post's Edit box and save it like that. Helps me to avoid double posting sometimes, especially when things happen in quick succession.
I've been using forums for basically my entire life, so when I tried introducing a friend of mine to IU awhile back, it was actually very interesting rediscovering the learning curve required to use them first-hand with them. They had only ever used the main social media type sites, Discord, and similar group chat programs that use a very similar format to each other. They had a very tough time wrapping their head around navigation between sub-forums, how specific each thread was, all the little buttons scattered across every page. Social media is so streamlined now that a lot of these features either don't exist or are completely different. It really is a completely different skill-set.
After 20+ years of using sites formatted like this one, it's very easy to forget that it can be quite a daunting thing to learn how to navigate properly or post with the precise etiquette. If it doesn't exist already, I believe a Help / Guide to the forum could actually do some good.