After fulfilling the prerequisite steps, create a new directory dedicated to your project, as follows:

mkdir Bitcoin_payment && cd Bitcoin_payment

In your workspace, create two new subdirectories: a keys/ directory for storing your keys and certificate, and a views/ directory for storing the web pages and scripts.

To install all the requisite dependencies, create a package.json file from inside the Bitcoin_payment/ directory:

{
  "scripts": {
    "start": "node server.js"
  },
  "dependencies": {
    "bitcore-lib": "^0.15.0",
    "bitcore-payment-protocol": "1.2.2",
    "body-parser": "^1.18.3",
    "express": "^4.16.3",
    "request": "^2.88.0",
    "underscore": "^1.9.1"
  }
}

Then run the following command:

npm install

This will install all the Node packages you need for setting up and running the project.