Can't get back to Mac OS after using bootcamp to install windows 10

Please help. I just used bootcamp to install Windows 10. The first time windows 10 opened, the installer for boot camp popped up but i accidently closed and canceled the install. Now I'm trying to find a way to install it but I dont see anything I can click to get the page back. I want to go back to Mac OS but I dont know how since i cant access or install bootcamp from windows 10. I'm scared and I just wanted my computer back the way it was. Is there any other way to return to Mac OS besides with the bootcamp application?