TBH, i dont like seeing automatic messages being broadcasted in admin chat when i am in a server. They get really annoying fast. Those should be saved for admins actually writing a message.(and hopefully a message that is worth reading.) i personally prefer messages in the bottom left side of the screen.
anyways, the best advice i can give is look at the existing code. use your in game knowledge, and compare how things work in code to in game. you'll find most things you need in the scripts, MT, presentation, or scene props file. you can find the operations that you can use in the header operations file. Search for stuff in the files and see how they are done.