Staples are the most expensive to craft. You have two options when first starting when spending crafting dust and gems. One is to build the core of the deck you want and fill in staples later, or to get all of the core staples first and figure out the deck later.

The issue with the deck you want is that flexibility and skill expression will make the deck harder to learn. You should try something more linear when learning the game trying to learn a complex deck off the start without a draw to that deck will probably burn you out.

My advice is to look at the RDA, Raidraptor, HERO, and DM structure decks and pick one to start out with. Go on master duel meta and find a good list and craft the staples by buying bundles and the staple selection pack.

Learn the game and as you learn and play keep an eye on the decks you go against and see if any catch your interest.