I have private git repository with 2 git submodule (Backend - Laravel API REST & Fronted - AngularJS).
Once the developer clones the project, he must run a setup process to initialize this project.
For example:
git submodule init
git submodule update
cd backend
composer update
mv .env.example .env
php artisan migrate --seed
cd ../frontend
bower install
etc ...
Sounds like you need a script that will do this work for you.
Write the script, place it in your root folder of the project and tell user to run it. Using script will make your life easier if you modify the script and its content.
You simply update the script skipping the need to update your doc unless you have to.
If you use git (any OS) you can write bash/sh file bu simply copying the content in your question to the file and pushing it to git. Just make sure you set the execute permissions on the file so your users will be able to execute it.
#!/bin/sh
git submodule init
git submodule update
cd backend
composer update
mv .env.example .env
php artisan migrate --seed
cd ../frontend
bower install