Update contact info on email verification

Hi all I’ve used the following code to create my login.

I want to know how I can update a field in my contact info once the email verification takes place.

Any help would be appreciated.
Someone pointed me to the update contact info api, but I dont understand how to put it together.

Basically I want to manually approve the members but after they have verified email.

/*******************************
 * backend code - register.jsw *
 *******************************/
import wixUsersBackend from 'wix-users-backend';

export function doRegistration(email, password, firstName, lastName) {
  // register the user
  return wixUsersBackend.register(email, password, {
    "contactInfo": {
      "firstName": firstName,
      "lastName": lastName
    }
  } )
  .then( (results) => {
    // user is now registered and pending approval
    // send a registration verification email
    wixUsersBackend.emailUser('verifyRegistration', results.user.id, {
      "variables": {
        "name": firstName,
        "verifyLink": `http://yourdomain.com/post-register?token=${results.approvalToken}`
      }
    } );
  } );
}

export function doApproval(token) {
  // approve the user
  return wixUsersBackend.approveByToken(token)
  // user is now active, but not logged in
  // return the session token to log in the user client-side
    .then( (sessionToken) => {
      return {sessionToken, "approved": true};
    } )
    .catch( (error) => {
      return {"approved": false, "reason": error};
    } );
}

/*********************************
 * client-side registration code *
 *********************************/
import wixUsersBackend from 'wix-users';
import {doRegistration} from 'backend/register';

export function button_click(event) {
  let email = // the user's email address
  let password = // the user's password
  let firstName = // the user's first name
  let lastName = // the user's last name

  doRegistration(email, password, firstName, lastName)
    .then( () => {
      console.log("Confirmation email sent.");
    } );
}

/**************************************
 * client-side post-registration code *
 **************************************/
import wixLocation from 'wix-location';
import wixUsersBackend from 'wix-users';
import {doApproval} from 'backend/register';

$w.onReady( () => {
  // get the token from the URL
  let token = wixLocation.query.token;

  doApproval(token)
    .then( (result) => {
      if (result.approved){
        // log the user in
        wixUsersBackend.applySessionToken(result.sessionToken);
          console.log("Approved");
      }
      else {
        console.log("Not approved!");
      }
    } );
} );