Hi,

Yes, you can refer to the official NMAT by GMAC guide for the NMAT preparations. The guide involves a lot of questions, sample papers and solved examples which help you prepare for the actual NMAT examination. In addition to that, you can prepare from the NMAT by GMAC free mock tests which are available as they are really good and very similar to the actual NMAT exam. After you've prepared from the free mock tests, you can also give the paid mock tests as from that you can know your improvement.

I hope this helps,

All the best