Volume controller can control the beep sound and alarm.
However, since it is an analog motor type timer, you may hear clock ticking sounds when motor is moving, and it cannot be muted.

No, it is not compatible with tablet PCs.

minee uses two plastic paper to express flow of the time.
In order to prevent the parper from falling out, the minimum area should overlap.

If it's your first time receiving it, it might not open well because it's a new product.
Press hard on the middle of the cover, hang your fingertips on the cover groove and open it by pulling it up.

No, set time will be maintained even when the battery is removed. 
You only need to use app when you need to change the time setting.

If the timer is running, please reset it first and change time setting.
Newly set time will be applied from next session.