a$ = "Hello,How,Are,You,Today" '               | Initialize original string.
FOR na = 1 TO LEN(a$) '                        | Start loop to count number of commas.
  IF MID$(a$, na, 1) = "," THEN nc = nc + 1 '  | For each comma, increment nc.
NEXT '                                         | End of loop.
DIM t$(nc) '                                   | Dim t$ array with total number of commas (nc). Array base is 0.
FOR nb = 1 TO LEN(a$) '                        | Start loop to find each word.
  c$ = MID$(a$, nb, 1) '                       | Look at each character in the string.
  IF c$ = "," THEN '                           | If the character is a comma, increase the t$ array for the next word.
    t = t + 1 '                                | t = token word count. Starts at 0 because array base is 0.
  ELSE '                                       | Or...
    t$(t) = t$(t) + c$ '                       | Add each character to the current token (t$) word.
  END IF '                                     | End of decision tree.
NEXT '                                         | End of loop.
FOR nd = 0 TO t '                              | Start loop to create final desired output.
  tf$ = tf$ + t$(nd) + "." '                   | Add each token word from t$ followed by a period to the final tf$.
NEXT '                                         | End of loop.
PRINT LEFT$(tf$, LEN(tf$) - 1) '               | Print all but the last period of tf$.
END '                                          | Program end.