To make a topic, you need to go to a board you can create a topic in like the Discussion board then press "New Topic" (https://prnt.sc/oRw39AdG95xg) at the top right then add whatever subject you want as if you just made this topic. To make its color like the screenshot you added is to make the topic a sticky topic. A topic can be stickied only if you're a moderator in that board.
The moderator of the board can stick it or a staff. :o7:
I Don't know how to stick it and iam Moderator in Board because im asking :fp:(https://i.pilo.ovh/images/sopfC.jpg)