Once the segment is selected, right-click on the selection and choose Layer via Cut from the menu. Once the selected piece is converted into a new layer, you will be able to move it about freely.
Repeat the process as before to crack the entire text. You will have a lot of layers on your hands at this point. One by one, select the layers on which the individual pieces reside and using the arrow keys, nudge them up and down and to the sides (with Move Tool selected). The spaces we are creating will allow the light to filter through.
Once you’ve moved all the individual pieces, select all the additional layers and go to Layer > Merge Layers. Name the new merged layer “Parts”.
Pick a soft edged brush and reduce the brush opacity and flow to 40 %.
Create a new layer just above your background layer and begin applying white between the cracks. Try to vary the tone, making it very bright in some areas and less so in others.