Hi there
I have ESP-01, ESP-12 & 12E boards, a Mac as well. I have been making IoT projects using these boards for over an year. You are stuck with simple problem of changing modes from Running flash code to Programming mode, while uploading sketches. From the description I gather that you have installed the ESP8266 modules for the Arduino IDE successfully.
Do let me know if you'd like to discuss more. Which ESP board do you have?
cheers
Akash