Specify the rhythmic composition of the tuplet. On the top part of the screen Finale is asking, “How many notes of what rhythmic value are to fit in the space normally allotted to how many of what value?” Enter the number of each rhythmic value in the text boxes. Specify the rhythmic value itself by selecting the rhythmic-value from the drop-down menu.
For example, to define a standard quarter note triplet, you could fill out the values either as “3 (quarters) in the space of 2 (quarters),” or “3 (quarters) in the space of 1 (half).”