The process for enabling a password sits at a pods level.
Select the pod on which you want to put a password for access.
Then click 'Share' in the top right hand corner of the screen of the screen.
Then select the Access control option within the Advanced options.
Then click the switch to enable 'Password protect' and type in your chosen password.
Note - If you change the password of a pod, anyone who entered the previous password correctly will now have to enter the new password to gain access.
Additional Note - anyone who knows this password can access the pod, and there is no way of stopping people from sharing the password with friends/colleagues/lovers.