This question already has an answer here:
Extending the default Magento One Page Checkout:
is there a way to combine in one single step Payment Method (Step 4) and Order Review (Step 5) ?
If not possible is there a way to revert their order ?
Because usually a customer first has to check if the order then can send the payment.
Using paypal as unique payment method this doesn't happen.
After the point 4 the user is automatically redirect to the paypal page.
I know that other users marked this question as duplicate but unfortunately they didn't read well the solution they gave me: OneStepSolution Provided
In my extension I will not restrict myself to any specific scenario; instead, I will attempt to build a OneStep checkout as a replacement to the fully fledged Magento OnePage checkout.