There are also tons of creatures that arent changelings but provide useful abilities like creating Treasures with Magda, Brazen Outlaw, granting islandwalk from Master of the Pearl Trident, or making each other creature indestructible with Knight Exemplar
In practice its a pretty straightforward one-two punch: Build up more mana than you might otherwise be able to turn after turn, a strategy referred to as ramp in the vernacular, and then use it to summon your scaly friends en masse
Along with the MTG Arena tutorials weve already mentioned, Wizards of the Coast has great introductory explainers that explain the very basics
Make Magic happen with amazing mash-ups
Its an Oblivion Ring stapled to a mana ramp Aura
Let's take a look at all of the contents, then I will highlight a few specific slots with more information