To peg a currency is quite easy. If you want your currency to devalue you buy some other currency and pay with yours. If you want to add value then you sell your foreign currency reserves and accept payment in your own currency. It's not rocket science. Many countries do this to not so much FIX their currency to another but to add stability, remove the big fluctuations. The Swiss Franc is controlled like this.
You will probably find the Rand will be pegged between R11 to R12 to the Euro IMO. The Euro is our main trading currency and it makes sense to try and stabilise the Rand so that all importers and exporters will know more or less what the will have to pay or receive in the short to medium term.
It also means that when Brazil has a bad coffee crop the Rand doesn't go for a ball of chalk just because South Africa is also an emerging economy. Just means you will pay more per cuppa.