SHELL

cypress install

cd /your/project/path
npm init
npm install cypress --save-dev

install cypress

npm install cypress or npm install cypress --save-dev // Make sure that you have already run npm init

./node_modules/.bin/cypress open  //to open cypress window, will take 30 secs

install cypress

//Install Cypress
npm install cypress --save-dev or yarn add cypress --dev

//Open Cypress
node_modules/.bin/cypress open 
or 
add "cypress": "cypress open" in your package.json then npm run cypress

cypress installation

# Install Cypress via npm:
cd /your/project/path
# This will install Cypress locally as a dev dependency for your project.
npm install cypress --save-dev

# Installing Cypress via yarn:
cd /your/project/path
yarn add cypress --dev

# more info:
https://docs.cypress.io/guides/getting-started/installing-cypress