Let's pick it apart to learn how it works... 

... Get the length of the text string
StrLen "[Word]" "[WordLen]"

... Initiate a loop until X equals the length of the text string
While "[X]" "<=" "[WordLen]"

... Pick apart the string one character at a time. 
... Store this charater in variable C
 SubStr "[Word]" "[X]" "1" "[C]"

... Search this Alphabet string for the match of C and store 
... the resulting postion number in the variable CP 
 SearchStr "[C]" "abcdefghijklmnopqrstuvwxyz" "[CP]"

... Only act if the character C was found in the Alphabet string 
... At this point CP has a numerical value. This value is the position 
... of the C character in the Alphbet string
  If "[CP]" ">" "0"

... Delete the character at position X
    StrDel "[Word]" "[X]" "1" "[Word]"

... Pick out the uppercase character from the same position 
... it was found in the lowercase Alphabet string
... Store this new character in the variable C
    SubStr "ABCDEFGHIJKLMNOPQRSTUVWXYZ" "[CP]" "1" "[C]"

... Place this uppercase character into the same position 
... where the lowercase character was deleted from
    StrIns "[C]" "[Word]" "[X]" "[Word]"

... all done with this character - get outta here
  EndIf

... Add 1 to the X loop to move on to the next character in the text string
  Math "[X]+1" "0" "[X]"

... Visual indicator
  SetVar "[Progress]" "[Progress]•"

... The bottom of the loop. If X is less than or equal to 
... the length of the text string then we will go back to 
... the While line to repeat the sequence.
EndWhile