To set ANDROID_HOME, variable, you need to know how you installed android dev setup.
If you don't know you can check if the following paths exist in your machine. Add the following to .bashrc, .zshrc, or .profile depending on what you use
If you installed with homebrew,
export ANDROID_HOME=/usr/local/opt/android-sdk
Check if this path exists:
If you installed android studio following the website,
export ANDROID_HOME=~/Library/Android/sdk
Finally add it to path:
export PATH=$PATH:$ANDROID_HOME/tools:$ANDROID_HOME/platform-tools
If you're too lazy to open an editor do this:
echo "export ANDROID_HOME=~/Library/Android/sdk" >> ~/.bashrc
echo "export PATH=$PATH:$ANDROID_HOME/tools:$ANDROID_HOME/platform-tools" >> ~/.bashrc