$data = array('scope' => "ZohoBooks.fullaccess.all", 'client_id' => $CLIENTID, 'client_secret' => $CLIENT_SECRET, 'state' => "testing",  'response_type' => "code", 'redirect_uri' => "https://www.zoho.com/in/books/", 'access_type' => "offline");

curl_setopt_array($curl, array(

CURLOPT_URL => "https://accounts.zoho.com/oauth/v2/auth",

CURLOPT_RETURNTRANSFER => true,

CURLOPT_ENCODING => "",

CURLOPT_MAXREDIRS => 10,

CURLOPT_TIMEOUT => 30,

CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,

CURLOPT_CUSTOMREQUEST => "POST",

CURLOPT_POSTFIELDS => http_build_query($data),

CURLOPT_HTTPHEADER => array(

    "content-type: application/x-www-form-urlencoded;charset=UTF-8"

),

));

$response = curl_exec($curl);

$info = curl_getinfo($curl);

$err = curl_error($curl);

The statement "On this request, you will be shown with a "user consent page" in url "https://www.zoho.com/books/api/v3/#oauth" in step2 is the context.