A One4All card is already 'activated' when you receive it. (The 'activation' part is done by the cashier or website that sold it).
It's basically a pre-loaded debit card that can only be use in certain stores (or on certain websites). The only reasons that one might need to go online to do anything are to check how much credit is left on it and/or to top it up with additional credit.
A full list of places that you can spend the credit on the card can be found here:
https://www.one4all.com/retailer.html