Swipe in from the right edge of the screen, and then tap Search. (If you're using a mouse, point to the upper-right corner of the screen, move the mouse pointer down, and then click Search.)
Enter the app name, or scroll until you find it.
Swipe down on or right-click the app to select it.
Tap or click Pin to taskbar.
Right click on an existing icon on the task bar and choose Unpin.