For a 3.3V output voltage you need to leave the SEL pin unconnected or floating.
MAX77827
Production
The MAX77827 is a high-efficiency buck-boost regulator targeted for one-cell Li-ion powered applications with the lowest typical quiescent current in the...
Datasheet
MAX77827 on Analog.com
For a 3.3V output voltage you need to leave the SEL pin unconnected or floating.