In the Timeline window, select the layer used for the individual letter that doesn't have the 'show' action in it, select Frame 3 and select Transform from the Add Action button. Select the Transform tab in the popup window, and set the scale to 50% (for reasons of simplicity, I chose to only change this value in this tutorial). (see Fig.4) Fig 4
Select the frame after this first transform effect, and on transform tab in the subsequent popup, change the Scale value to "Resize back to 100%". Then right-click the next frame after this second effect in the Scene layer, select "Goto Frame" and enter 0. In the same frame, in the text layer not used to perform the effects, right-click and select "Show". Your Timeline tab should now look like Figure 5. Fig 5