There's no shame in not knowing everything about longboards! We, the Stella Longboards team, recognize how intimidating the skate industry can be; we would like the teach you some of the components that go onto your board!
A few items are necessary in order to make your longboard rideable, and in the future you might want to consider replacing components due to age or water damage:
Wheels: There isn't anything new that we have to explain about wheels - we trust you know what wheels are! Just know that the size (diameter) and softness (durometer) play a big role in how your board rides.
The Stella team has made sure that your boards collection of components match the style of riding you are going to do, but as you learn more you can make some modifications how you would like. Each wheel description will tell the purpose of you wheel so you do not have to guess what it is capable
The smaller/harder wheels are usually best for short-distance cruising, freeride and tricks.
A larger/softer wheel is better for long-distance cruising, carving, downhill and freestyle.
Trucks: The trucks are that "T" looking metal piece sandwiched between your longboard deck and the wheels.