Getting your team to work like a team can often be helped by setting up some initial "rules" that everyone on the team agrees to follow. By laying the groundwork early in the formation of the team, you can avoid misunderstanding and even deliberate "misconduct" by always going back to the rules. Instead of, "No, this is how we're supposed to do it," you'll be able to say, "No, we all agreed to work this way."
Every team should create their own ground rules. If they are imposed from outside the team, they become a lot harder to enforce -- the developer can just say, "Hey, I didn't agree to do that." So, in your very first gathering of your team, we recommend setting up some ground rules to help govern future behavior and decisions. While you want your team to come up with these rules, here are some good ideas to include on the list...
- We all agree to follow Scrum as defined in the Scrum Guide (www.scrumguides.org).
- If I don't want to be on the team, I will take steps with management to get removed from the team (the "escape clause").
- We will, to the best of our abilities, be on time for, and participate in, all team events (e.g., Sprint Planning, Daily Scrums).
- We agree to support team decisions, even if we disagree with those decisions.
- Make sure everyone gets heard.
- Stay focused on the Sprint Goal.
- Don't say, "no," say "Sure, add it to the Product Backlog and let the Product Owner prioritize."
This short list can get you started, but make sure it's the team that creates the list -- don't impose it on them.