What is the difference between the “Settings” button in the main and additional (side) menus?

“Settings” button in the main menu: the ability to change settings with the parent device on the selected child device. 

For example, you want to block access to settings on a child device (available for child Android only) from your device. In this case, open the Kroha app on your device > Select your child's device in the device list > You will be taken to the main menu > Here, select the “Settings” section > Switch on the toggle next to “Block Access to Phone Settings”.

The “Settings” button in the additional (side) menu is an option to change settings on the device on where you opened the Kroha app. 

For example, you want to block access to the settings of a child's phone (available for child Android only). In this case, open the Kroha app on your child's device > Tap the gear icon > Select “Change parental restrictions” > Go to the side menu (the three bars on the top right or swipe from right to left) > Go to “Settings” > Enable the toggle next to “Block Access to Phone Settings”.