If there is a problem and you can't complete and mail the project in the month's time, e-mail the Robin leader, the owner of the project, and the person to receive it next. Add a welcome letter when sending your Robins. This way the other stitchers know a little about you. It's really wise to keep in contact with all stitchers involved in your project. That way you can get the feel of things.
Some stitchers send charts with their fabric.
Others only pick a theme and let the other stitchers find a chart to fit the theme. Try looking through old magazines. Many of the horror stories heard in chat had to do with stitchers participating in a Robin who were at different levels of experience. It is very discouraging to high caliber stitchers to get in a Robin with a beginner. And it's intimidating to beginners to get in a group with experienced stitchers.