Is there a way to apply a pattern to unit loads?
1) Create your pattern(s) under the Patterns Manager (Components > Operational > Patterns)
2) Associate the pattern(s) to your unit load types via the Pattern Setups Manager (Components > Operational > Patterns > Pattern Setups)
3) Select the Pattern Setup in the calculation option set assigned to the scenario in question (Analysis > Calculation > Options)
For more details, see Quick Start Lesson 3 Part 2 the last section in there titled "Adding Sanitary Loads".