Simply log into your SoFi savings account and click on 'Add Vault' next to the Vaults icon to get started. 
Next, select from a number of pre-populated vaults.
You may then customize your vault if you'd like. 
Add the amount to be transferred to the new vault. Once completed, the available 'Spending balance' will appear. 
Finally, select 'Add money' to finalize. A confirmation screen will appear, click on 'Done' and your new vault is ready to go.
For instructions on how to move Funds from your SoFi checking or savings balance to your new Vault click here.