User selection Feature

Hello,

I need a user-selection feature added to our website to automate this process for our website visitors. I have standalone html codes for this user-selection, which works well when tested on https://www.w3schools.com/

Here are the html codes, which you can test by yourself. I need this to be implemented into https://voipvoice.co.uk/business-voip/ ---> See first Table, User(s) row
=====================





STANDARD

body {
font-family: Arial, sans-serif;
margin: 0;
padding: 20px;
background-color: #f4f4f9;
}
.container {
max-width: 600px;
margin: 0 auto;
background: #fff;
padding: 20px;
border-radius: 8px;
box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}
h1 {
text-align: center;
}
.form-group {
margin-bottom: 20px;
}
label {
display: block;
font-weight: bold;
margin-bottom: 10px;
}
input[type="number"] {
width: 100%;
padding: 10px;
font-size: 16px;
border: 1px solid #ccc;
border-radius: 4px;
}
.total {
font-size: 18px;
margin: 20px 0;
text-align: center;
}
.btn {
display: block;
width: 100%;
padding: 10px;
font-size: 16px;
color: #fff;
background-color: #007bff;
border: none;
border-radius: 4px;
cursor: pointer;
text-align: center;
}
.btn:hover {
background-color: #0056b3;
}


function updateTotal() {
const pricePerUser = 5;
const userCount = document.getElementById('userCount').value;
const totalPrice = pricePerUser * userCount;
document.getElementById('totalPrice').textContent = `Total Price: £${totalPrice}`;
}




STANDARD

Number of Users:


Total Price: £5
Proceed to Checkout



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