Help with REDitor add

How do you add players with RedItor, I added some on the slots but they don't show up. Sorry I'm a complete noob to this.

It's best to create new players in-game, and then edit them with REDitor as necessary. With roster modding, always do whatever you can in-game before externally editing the file. That's the best way to make sure everything works as intended, and that you don't corrupt the file or otherwise damage the data.