add hint about stash/controller accounts (#31)

docs/staking/nominate.mdx

@@ -16,7 +16,7 @@ Being a nominator does not require running your own node or worrying about onlin
 
 To nominate your VARA tokens, go to the Polkadot.{js} app, navigate to the Network → Staking → [Accounts](https://polkadot.js.org/apps/?rpc=wss%3A%2F%2Frpc.vara-network.io#/staking/actions) section, and click `+ Nominator`:
 
-1. Select the stash and controller accounts, along with the amount of value you wish to bond.
+1. Select the stash and controller accounts, along with the amount of value you wish to bond. You can see in the screenshot what Stash and Controller accounts are. If you have not created your controller account, you can use the same one for both.
 
 ![setup nominator](./img/nominator-1.png)