This is a guideline for installing fastlane on your mac.

1- Install Xcode command line tools:

xcode-select — install

2- Install Homebrew:

https://brew.sh/

3- Install ruby. Ruby is already installed on Mac but I highly recommend to install a new version with brew. Check below links if you encounter any problem:

brew install ruby

https://stackoverflow.com/questions/39381360/how-do-i-install-ruby-gems-on-mac

https://stackoverflow.com/questions/6482738/installing-ruby-gems-not-working-with-home-brew

4- Install bundler:

https://bundler.io/

5- Install fastlane:

sudo gem install fastlane

6- Run the command below to check if fastlane is installed:

fastlane -v

7- Go to your project’s root directory and run the command below to initialize fastlane in your project.

fastlane init

This will create Gemfile and also a fastlane directory in your project. Now you are ready to create your custom lanes in your Fastfile.