This section requires that your devices are configured with a lock screen, this is quite standard across mobile devices however, sometimes, organisation do not configure their Windows/Mac devices with a lockscreen.
A5.9 requires you to confirm if the above is applicable to your assets.
In the case of A5.10 you should state what controls are implemented for your devices. In the case of mobile phones and tablets they tend to have either biometrics or 6 characters pins by default.
For Windows devices you can set up a lock screen and then use biometrics or PIN with Windows Hello, or by default a password
Depending on the Mac device you have you can use similar authentication to the above.
For Linux by default it’s password once the screen is locked.