Each page is a slightly different activity. Page 1 is matching capital letters with capital letters (the stickers are usually caps). Page 2 is lower case. Choose one.
Give students a page of alphabet stickers and have them stick them on/next to the same letter on the WS.
Disclaimer: I "borrowed" someone else's Alphabet worksheet, scrambled the order and changed the title.
Alternate activity: Have students cut out the squares and put them in the right order.