Activate the Blue Essence Orb and open all the Champion capsules, those are free to open and how you get Blue Essence (IP), now. They give you shards for characters that you can either make Permanent at a discounted IP price, or be grinded into essence.
That's really the only thing that actually matters with the crafting mechanics, because the rest of it has to do with skins/loading screen add-ons, or requires real money.
You require 3 Key Fragments to make 1 Key. You get fragments at random for "keeping it sportsmanlike" (getting Honor and at random, I'd guess). You use keys to open Hextech Chests, which you get from personally achieving or being queud with someone that gets an S- or higher in a game. Only one chest per champion per... Season? Every few months? Also you can only get a certain number of chests every few days. You can see how many keys, chests and Orange Essence (used for skins) you have in the bottom-left corner of the Loot menu. Hextech Chests are just for cosmetic I think?
Mastery Tokens confuse me still tbh (what's a champion permanent?), but they just let you level up your character's level from 5 to 6 and 7. Just changes your loading screen banner when you use those champs. Not really important for the game itself.
Oh and I have no idea what a Gemstone is lol, never had one of those
