Question

which buttons should be pressed to select all files and folders​

Answer 1

Answer:

To select several files and folders, hold down the Ctrl key when you click the names or icons. Each name or icon stays highlighted when you click the next one. To gather several files or folders sitting next to each other in a list, click the first one. Then hold down the Shift key as you click the last one.

Hope it helps you...

Answer 2

Answer:

"Sellect All" button

shortcut key for it Ctrl+A