how to submit form with multiple form field bearing the same name to database table in flask - python-3.x

Question

I trying to submit items in a shopping cart to a database table but I can't get a clear understanding or how to implement it using the documentation on WTFORMS and other online materials I came across.
I have this forms in my forms.py:
class CartForm(Form):
amount = IntegerField('Price')
item_name = StringField('Product Name')
quantity = IntegerField('Quantity')
item_total_amount = IntegerField('Item Total')
class MainForm(FlaskForm):
total_amount = IntegerField('Total Amount')
cart_items = FieldList(
FormField(CartForm),
min_entries=1,
max_entries=20)
and this is the form in my template:
checkout.html
<form name="cart" action="{{ url_for('posts.checkout') }}" method="post"
enctype="multipart/form-data">
<table class="timetable_sub">
<thead>
<tr>
<th>Product Name</th>
<th>Quantity</th>
<th>Price</th>
<th>Total</th>
</tr>
</thead>
<tbody>
{% for item in user_cart %}
</tr>
<tr name="line_items">
<td><input type="text" name="item_name " value="{{item.item_name }}"></td>
<td><input type="number" name="quantity " value="{{item.quantity}}"></td>
<td><input type="number" name="amount" value="{{item.amount}}"></td>
<td>
<input type="number" name="item_total_amount "value="item_total_amount
</td>
</tr>
{% endfor %}
</tbody></table>
<input type="number" name="total_amount" value="total_amount">
<input type="submit" value="Register">
</form>
I will appreciate a tutorial link or code base that can help me send this looped for fields to the database table