I have no idea why a new map doesn't start with the first card added, but hopefully, they will fix this in the near future. Until that time, you can click on another here link or press the N key on your keyboard.
You can start typing in the title of your card. You can use markdown in the titles of your card. This lightweight markup language enabled the creators of this app to skip adding a rich text editor, and it makes the app and your work much faster. You can simply type in the text, and you don't need to worry about markdown if you don't want to.