Help for Accounting Module

[CSCSxx]

Hello,
I'm currently trying to understand the accounting module, but I can't get any further, even on your demo platform I couldn't understand how to set up a purchase transaction via the automatic booking of the ledgers.

I have set the following:
Purchase:
Credit Ledger = Sundry Creditors
Debit Credit Ledger = Purchase Accounts
Payment Credit Ledger = Bank Accounts
Payment Debit Ledger = Sundry Creditors

And for inventory:
Credit Ledger: Purchase Accounts
Debit Ledger: Current Assets

Then I create a purchase invoice, accept the payment and make the goods receipt...
When I then call up the Profit&Loss or Balance Sheet report, everything is 0

If I then play a little with the accounts, or if I choose not to carry out the goods receipt or the payment of the invoice, figures appear - but no matter what I set, the balance sheet and/or Profit&Loss is never correct.

Furthermore, I have noticed that the taxes preset for the purchase of goods are correctly broken down in the purchasing account, but not in the accounting module, although I have set up an account for taxes...

Can you possibly provide better instructions here?
Thank you very much.
Used Version: 4.7.1