Hi there!
If you just want to write on it, double click on the board. You can't be in edit mode. Just place it in your room, save, then double click it. The workspace will open after that for you to draw on. You can keep the box checked so your work is locked and no one who visits can mess it up. You can uncheck it and your guests can write on it, erase it, etc. Click save when you are done.
Welcome to the forum!