1. In Aloha browser click 3-dot icon in the upper right corner:
2. In the menu at the bottom click 'Additional settings' button:
3. Then, click Passcode:
4. Enable passcode toggle:
5. Insert 6-digit pass:
6. Then click 'Continue' button:
7. Again insert the pass and click 'Confirm' button:
You can then set up Auto-lock duration from 1 minute to 1 hour:
And select Lock Areas - whole device, Private tabs or both: