How to perform matrix multiplication in Mixing Columns step of AES? I am studying AES and trying to implement it. But I am having difficulty understanding the Mixing Column step. In that step we have to perform matrix multiplication between the state matrix and another fixed matrix. Here is the example given in the material I am studying from:

I am not getting the 03*2F part. How did it turn into (02*2F)xor2F? Is the material correct or does it have some mistake?
Edit:
I got that 3 = 2 xor 1 hence 3 x 2F = (2 xor 1) x 2F = (2 x 2F) xor 2F but what in case if 4 x 2F? 4 = 2 xor 6 so (2 xor 6) x 2F then what?
If you want to implement it, I suggest you read the spec.  The material you were given is probably not enough to implement it.

The reason that looks confusing is that it is not ordinary multiplication; it is multiplication in a finite field.  There are lots of resources where you can learn about finite fields.