On the official site)

https://nash.io/
https://medium.com/nashsocial/nex-extension-and-lottery-q-a-667e56f58e4a

To provide a contributing wallet address, you will need to download and install our Chrome NEX wallet extension. The wallet address that you provide in the lottery registration needs to be the same address that you provide for KYC. If you are a successful participant, and must match the address you send NEO/GAS from in the ICO contribution.

Then fill 5 fields: full name, document type, country, document number, and NEO address.
Thats all!