How to expand current DB (1 Viewer)

I have a database for a dance school that holds all customer info.

I would like to try and add to this a payments section. Each person is billed £20 per month and what I would like to do is have £20 added to each persons bill at the beginning of each month and somewhere where I can enter payments made that will deduct from there balance.

I am really hoping that someone can guide to somewhere where I can start this. Any help or advice would be greatly appreciated.

Thank you

Add a new table tblPayments with fields & datatypes similar to this:

PaymentID (PK - autonumber)
CustomerID (FK - same as PK field in Customers table)
PaymentDate (DateTime)
PaymentAmount (Currency)
PaymentType (Text)
StaffInitials (Text) - optional
Notes (long text / memo) - optional

This table can handle payments in & 'out' (amounts due).
One of these types needs to be assigned as a negative amount
The balance is the sum of all payments

At the start of each month, run an append query to add a new payment record for £20 for each customer

Use a form (frmPayments) to handle all payments made

The purpose of the two optional fields is:
a) StaffInitials - person who enters details of payments made
b) Notes - used for additional comments as needed - using long text / memo allow users to enter several thousand characters if needed

i have this EXACT db. Dance school.
What you need is an append query to add 20 to the tCharges table. This appends to all Active customers. Hopefully you have these tables:
tCustomers
(and the following children of tCustomers)
tCharges
tBilling

Ranman256, Are these the only 3 tables you have?