If you're looking to play the giga pack there are two different ways to play, Creative and Survival! In Creative mode you can build whatever and do whatever you want, Anything!

In Survival mode you start your world with nothing and you collect materials to obtain weapons armor, and more, And also you can interact with NPCs that are found all over the minecraft world, You are recommended to follow a mod line, The order that you play the mods in!

 

Vanilla Minecarft

The Farlanders

Galacticraft

Twilight Forest

Superheroes Unlimited

Orespawn

 

No matter how you play the game, it will probably take a long time to discover everything you can do!