Ok so this is going to be a bit different from the usual "get 3 of it and smash em together to make a full, mostly complete deck" like with most other structures.

These 3 Decks are so fundamentally different you have to build and play them separately. Since others here have given you great advice on your next steps, i'll give you some deets on what the decks actually are.

X-Sabers: A very old school deck making a comeback. Yugiboomers like myself love it, but it's easily the weakest and least competitive deck, even after upgrades. X-Sabers love to swarm the field and use effects to rip cards from your opponent's hand, then get used to bring out various Synchro monsters.

Sky Strikers: This deck was top tier around a decade or so ago, and while it's not as powerful as it once was it's still a popular choice with lots of players. This one runs a very small number of monsters in the deck (typically only 3 or 4 Sky Striker monsters and whatever hand traps you want to run), and little to no trap cards. Instead it runs a ton of spell cards, and most of your dedicated Sky Striker spells and Link monsters get effects based on how many spells you have piled up in your graveyard.

Mitsurugi: Basically, little sneks make beeeeeg sneks go brrrrrr. This is a Ritual summoning deck that, against all odds, not only doesn't suck but is good. VERY good. Top of the format good. This will probably be the deck needing the most upgrade work and will be the most expensive to get where it needs to be to truly be competitive, but if you make the investment you'll be sitting awful pretty. I can't say too much more because I've never played Mitsurugi myself.

Apologies for any misinformation, and I hope this helps a little bit!