How can I close the perimeter between two surfaces?

To this first create a rectangle with the RECTANGLE command. Then use the CYLINDER command to create a cylinder. Finally use the ALIGN command to model the square shape in the cylinder.

To bring back the arrows on your object, go to Customize the user interface. Then search for Transformation-Gizmo show then choose and assign a button. Afterwards close, press this button and you will see the red lines. Lastly, go to Settings > Gizmo and enable Gizmo again. Then click done.

To check your keyboard and mouse update or change the USB port drivers the device is plugged into. If that is not done, it could cause improper device input for mice, keyboards, etc. To check functionality for machine USB ports, ensure the working of the ports by testing each with a device.

To remove unused maps on your computer go and sign into My Maps. Adjacent to the map that is to be removed, click on the three dots and select Move to trash. The map you removed will stay in the trash unless you empty out Google Drive.

To make object more transparent go to the visibility option in Object Properties. In this panel lower the visibility after selecting the object.