1) Follow Google Sheet API Tutorial

https://developers.google.com/sheets/api/quickstart/js

Step 1: Turn on the Google Sheets API

1.1. Use this wizard to create or select a project in the Google Developers Console and automatically turn on the API. Click Continue, then Go to credentials.
1.2. On the Add credentials to your project page, click the Cancel button.
1.3. At the top of the page, select the OAuth consent screen tab. Select an Email address, enter a Product name if not already set, and click the Save button.
1.4. Select the Credentials tab, click the Create credentials button and select OAuth client ID.
1.5. Select the application type Web application.
1.6. In the Authorized JavaScript origins field, enter the URL http://localhost:8000. You can leave the Authorized redirect URIs field blank.
1.7. Click the Create button.
1.8. Take note of the client ID in the resulting dialog. You will need it in a later step.
1.9. Click OK to dismiss the resulting dialog.

Step 2: Set up the sample

Create a file named quickstart.html and copy in the following code:

<!DOCTYPE html>
<html>
<head>
<title>Google Sheets API Quickstart</title>
<meta charset='utf-8' />
</head>
<body>
<p>Google Sheets API Quickstart</p>


<button id="authorize-button" style="display: none;">Authorize</button>
<button id="signout-button" style="display: none;">Sign Out</button>

<pre id="content"></pre>

<script type="text/javascript">
// Client ID and API key from the Developer Console
var CLIENT_ID = '<YOUR_CLIENT_ID>';

// Array of API discovery doc URLs for APIs used by the quickstart
var DISCOVERY_DOCS = ["https://sheets.googleapis.com/$discovery/rest?version=v4"];

// Authorization scopes required by the API; multiple scopes can be
// included, separated by spaces.
var SCOPES = "https://www.googleapis.com/auth/spreadsheets.readonly";

var authorizeButton = document.getElementById('authorize-button');
var signoutButton = document.getElementById('signout-button');

/**
* On load, called to load the auth2 library and API client library.
*/
function handleClientLoad() {
gapi.load('client:auth2', initClient);
}

/**
* Initializes the API client library and sets up sign-in state
* listeners.
*/
function initClient() {
gapi.client.init({
discoveryDocs: DISCOVERY_DOCS,
clientId: CLIENT_ID,
scope: SCOPES
}).then(function () {
// Listen for sign-in state changes.
gapi.auth2.getAuthInstance().isSignedIn.listen(updateSigninStatus);

// Handle the initial sign-in state.
updateSigninStatus(gapi.auth2.getAuthInstance().isSignedIn.get());
authorizeButton.onclick = handleAuthClick;
signoutButton.onclick = handleSignoutClick;
});
}

/**
* Called when the signed in status changes, to update the UI
* appropriately. After a sign-in, the API is called.
*/
function updateSigninStatus(isSignedIn) {
if (isSignedIn) {
authorizeButton.style.display = 'none';
signoutButton.style.display = 'block';
listMajors();
} else {
authorizeButton.style.display = 'block';
signoutButton.style.display = 'none';
}
}

/**
* Sign in the user upon button click.
*/
function handleAuthClick(event) {
gapi.auth2.getAuthInstance().signIn();
}

/**
* Sign out the user upon button click.
*/
function handleSignoutClick(event) {
gapi.auth2.getAuthInstance().signOut();
}

/**
* Append a pre element to the body containing the given message
* as its text node. Used to display the results of the API call.
*
* @param {string} message Text to be placed in pre element.
*/
function appendPre(message) {
var pre = document.getElementById('content');
var textContent = document.createTextNode(message + '\n');
pre.appendChild(textContent);
}

/**
* Print the names and majors of students in a sample spreadsheet:
* https://docs.google.com/spreadsheets/d/1BxiMVs0XRA5nFMdKvBdBZjgmUUqptlbs74OgvE2upms/edit
*/
function listMajors() {
gapi.client.sheets.spreadsheets.values.get({
spreadsheetId: '1BxiMVs0XRA5nFMdKvBdBZjgmUUqptlbs74OgvE2upms',
range: 'Class Data!A2:E',
}).then(function(response) {
var range = response.result;
if (range.values.length > 0) {
appendPre('Name, Major:');
for (i = 0; i < range.values.length; i++) {
var row = range.values[i];
// Print columns A and E, which correspond to indices 0 and 4.
appendPre(row[0] + ', ' + row[4]);
}
} else {
appendPre('No data found.');
}
}, function(response) {
appendPre('Error: ' + response.result.error.message);
});
}

</script>

<script async defer src="https://apis.google.com/js/api.js"
onload="this.onload=function(){};handleClientLoad()"
onreadystatechange="if (this.readyState === 'complete') this.onload()">
</script>
</body>
</html>

Replace the placeholder <YOUR_CLIENT_ID> in the copied code with the client ID you created in Step 1.