Go to Home → tap the Switch button at the top of the screen next to the account name → select the Demo tab → tap the account you want to adjust the balance for → tap the Adjust balance button → enter your desired balance amount and tap Confirm.
Your demo account starts with a default balance of 1,000.
You can top up your balance in increments of 10,000.
To do this, go to ‘Settings’ → ‘My accounts’ → ‘Demo accounts’, then click the ‘Top up 10,000’.