How to select gate and gate-source resistors and N-MOSFET for controlling a 5V load from 3.3V input?
A single MosFet can do what you want, provided you use an appropriate MOSFET. 

Because your GPIO can only output 3.3 volts, you need to carefully choose your MOSFET. Look at mosfet gate characteristics for gate threshold voltage. The FQP30N06L mosfet has gate threshold voltage of 1.0 to 2.5 volts, and your 3.3 volt system can easily supply this minimum threshold voltage. 

The link you provide does show additional resistors. Without further information from you, just go with the typical resistors shown.