putting an icon on the taskbar

You can drag an icon to the Quick Launch bar which is the collection of icons at the left end of the Taskbar adjacent to the Start button.

If these are not showing right click on the Taskbar > Properties and on the Taskbar tab check Show Quick Launch > OK

Right click on the Taskbar again and uncheck 'Lock the Task bar'

Drag the vertical dashed line at the right hand end of the Quick Launch bar a little to the right.

Drag your icon from the desktop to the Quick Launch bar and release the left mouse button.

Drag the vertical dashed line at the right hand end of the Quick Launch bar up to the icons

Right click on the Task Bar and check 'Lock the Task Bar'.