How to connect the NFC Shield to an Arduino UNO?

I’m using the libnfc to connect to the NFC shield… however when I plug in the NFC shield on top of the Arduino UNO it doesn’t work.
It doesn’t find the NFC in the software.

I’ve read that when using a Seeeduino this must be switched to 3.3V - can somebody help me with a succesful wire schematic?

Thx in advance, Luc

I don’t very understand what’s the mean of libnfc which you said?
And we can use NFC shield with seeeduino under 5V,not must be switched to 3.3V.
And the way how to connect NFC shield to Arduino uno is the same to the way which connecting seeeduino.
So , please show your qusetion more clearly.