Replace the random integers between 0 and 4 on RandomLED.vi with your newly created RandomIntegerMinMax subVI:

• Open RandomLED.vi
• Save it as RandomLED_SubVI.vi
• Replace the steps to create random integers between 0 and 4 with your subVI
• Connect min/max with 0 and 4, respectively 
• Save your VI and check that it works as planned

Inspiration: