how to input words from array to GUI?

hi... how can i create wordings from array and put it on GUI...

describing : i have a GAMEOBJECT with Text Mesh on... and another object to hit the GAMEOBJECT. Once being hit by the other object.

the GAMEOBJECT with the Text Mesh on it (let say the letter A), the letter will appear in a GUI box.

and the letters created are random arrangements from an array of words..

help please...

thank you...