Manager Issues

I’v been promoted as the manager of a software company for which i have been working for the past 4-5yrs.Right now the issue is that the guys whome i used to work with is finding it hard to digest my promotion and trying all sorts of things to smoke me off the post creating loads of issues.I’m keeping my cool since i don’t want to create a rough edge in the environment.What is your comments on this?How do you want me to handle this pressure?