Step 1

Open terminal by pressing 'command+space' buttons and type "terminal" and then press enter

Step 2.  Install xcode-select using following command:

xcode-select --install

Step 3. Open brew.sh on browser, you will find the command below 'Install Homebrew" keyword

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

copy, paste and run it on terminal

Step 4. After installing Homebrew, you will get two more command at the end of installation as below:

run the following 2 commands on terminal to install brew

echo 'eval "$(/opt/homebrew/bin/brew shellenv)"' >> /Users/<Mac user>/.zprofile
eval "$(/opt/homebrew/bin/brew shellenv)"

Step 5. Search for the python, you can run command 'brew search python'

Step 6. To install python, run the following command:

brew install python@3.8

Step 7. To set python path, run the following command:

echo 'export PATH="/opt/homebrew/opt/python@3.8/bin:$PATH"' >> ~/.zshrc

Step 8. Grab the Odoo source code, go to Odoo github on browser

install git by following command: 

brew install git

go in Odoo repository for community edition Select the version you want
You can see green button 'Code', click on it to find the link in order to clone the Odoo code

git clone https:github.com/odoo/odoo.git --depth1
cd odoo

to navigate to Odoo Source code

Step 9. there is requirement.txt file in Odoo directory, To have a look where you can find the library version to be installed and the different packages

Step 10. install pip3 and To check the pip3 version run the following command:

brew install pip3

pip3 --version

Step 11. Run following command :

pip3 install setuptools wheel

Step 12. To install PostgreSQL run below command

brew install postgresql

Step 13. Now, install openssl using below command:

brew install openssl

Step 14. To fix the error of psycopg2 we will run binary version of the psycopg2, run following command:

pip3 install psycopg2-binary --no-cache-dir

Step 15. Run the command again 

pip3 install -r requirement.txt

Step 17. Error with pillow for dependency issue

brew install jpeg

Step 18 

brew install jpeg--turbo

Step 19. lets back to the requirement.txt

pip3 install requirement.txt

Step 20. Let's start Odoo service now. 

To start the service of the Odoo run the following command:

brew services restart postgresql

Step 21. To create a user, login with posgres, run 

psql postgres

Step 22. You can create postgres user from the posgres terminal:

create user <username>

Step 23. Create database using below command:

createdb db15

Step 24. \q for exit

Step 25. 

python3 odoo-bin -d db15 -i base

Step 26. 

You will find your Odoo service has been started. If you find error for 'current limit exceeds maximum limit'

python3 odoo-bin -d db15 --limit-memory-hard 0

Step 27. 

To reinitialize the database run the below command

python3 odoo-bin -d db15 -i base --limit-memory-hard 0