I am copying the current guide below in case it becomes inaccessible.
Nu Exchange Integration
This guide will explain how you can integrate NuBits and NuShares into your exchange.
1. Download the daemon
From NuBits.com/download you can find a package containing the daemon for your environment. The daemon will be called “nud” or “nud.exe” depending on your platform.
2. Create a nu.conf file
Before running the daemon you will need to create a nu.conf file. Follow our creating a nu.conf file guide to learn how to create the file. Place the following into your file:
rpcuser=anyusername rpcpassword=anypassword server=1
If you are configuring NuShares you MUST add avatar=0 to your conf file
rpcuser=anyusername rpcpassword=anypassword server=1 avatar=0
3. Start the daemon
Run the daemon using the --daemon parameter
Ex../nud --daemon
This will start the daemon in the background and begin syncing the blockchain. Run ./nud getinfo to verify you can communicate with the daemon through RPC.
4. Point your exchange software to the correct daemon unit
Nu uses different port numbers for different units. The only units in the software right now are NuBits and NuShares, but this may change in the future. Use the following guide below to select the port number for the unit you’re configuring.
PROTOCOL PORT 7890
// Base RPC port used by the NuShares RPC server.
// Other unit RPC servers listen on RPC_PORT+1, RPC_PORT+2, etc.
RPC PORT 14001 // NuShares
RPC PORT 14002 // NuBits
// Same rules apply to testnet, but on different ports
TESTNET PORT 7895
TESTNET RPC PORT 15001 // NuShares
TESTNET RPC PORT 15002 // NuBits
// Peercoin ports used when communicating with the Peercoin wallet for dividend distributions
PEERCOIN RPC PORT 9902
PEERCOIN TESTNET RPC PORT 9904
Have your software point to the correct port number to interface with the unit you’re configuring. For example this is how we would communicate with the NuBits unit in the Peatio exchange software
"rpc: http://nuEx:123exch@127.0.0.1:14002";