Frankly your ability to come up with bizarre ideas and inability to clearly state problems or even to realise you need to ask before doing something that makes no sense at all does make me wonder whether you will ever manage to set up a store. But assuming you genuinely do want to set up your shop with osC, I suggest that you:
1) Do not even think of applying any add-ons to the store until you have got a working set up that will at least allow customers to select a product and complete the checkout process.
2) Do not bother about the 'look and feel' of the store, just use default fonts and layout.
3) Do ask how to set up Paypal instead of trying to invent and pursue some crazy idea about it (you need a Paypal merchant account and you will find all the settings you need to work with osC in your Paypal merchant account settings options).
4) Do not change any php file unless you understand what you are supposed to do to. If you are not sure, ask. Don't ask under a topic title that says nothing about your problem such as 'I don't believe it', because unless someone has time for idle curiosity they may not even bother to read what you don't believe. Even if they do, they won't answer if they think it's a wind up - and your posts so far are pretty much enough to make even the most patient person roll their eyes and decide not to respond. I'm not sure why I'm bothering myself.
5) Do make a backup copy first before changing any php file, so you can go back to the original if your change doesn't work.
The article you refer to says, in the relevant place:
The Distance Selling Directive applies to any consumer distance contract made under the law of an EU-Member State as well as the European Economic Area (EEA). It provides a number of fundamental legal rights for consumers in order to ensure a high level of consumer protection throughout the EU. These include:
Provision of comprehensive information before the purchase;
Confirmation of that information in a durable medium (such as written confirmation);
Consumer's right to cancel the contract within a minimum of 7 working days without giving any reason and without penalty, except the cost of returning the goods (right of withdrawal);
Where the consumer has cancelled the contract, the right to a refund within 30 days of cancellation;
This does NOT mean the goods have to remain in the shopping basket for seven days before shipping. It means that the customer has seven working days from the date of receipt of the goods to cancel if they are not satisfied (there are also exceptions). If you keep the goods in the shopping basket for seven days before shipping them all that will happen is the customer will probably be annoyed at the delay and they will still have the right to cancel for another seven working days after they do finally receive them. There is nothing new in this.
So far as a contribution is concerned, there are already ways to provide customers with information about terms and conditions of sale and shipping and returns information which I think could be adapted and worded to comply with providing the prescribed information. I already have DSR information in the shipping and returns box, I am, however, also considering providing a reference to it and a statement of agreement to it before the customer completes the order. I think that would do.