When the Isle of Armor Expansion Pass was first announced, it was revealed that the Slowpoke Evolution Chain would each be receiving a brand new Galarian Form. Little did Pokemon Fans know that the Slowpoke Evolution Chain would be the only Regular Pokemon Evolution Chain to be receiving such a thing. Because of this, players can only obtain two new Galarian Form Pokemon: Galarian Slowpoke and Galarian Slowbro.
When you first purchase the Pokemon Sword & Shield Expansion Pass, a mini event will occur at the Wedgehurst Train Station. There you will see a Galarian Slowpoke and will meet Klara (Sword) or Avery (Shield), ultimately being able to capture the Galarian Slowpoke. Once you reach the Isle of Armor, you will also notice a bunch of wild Galarian Slowpoke roaming free on the beach areas. Suffice to say, Galarian Slowpoke is rather common and all players won't have any issues catching multiple of them should they so please.
Because Galarian Slowpoke is rather easy to obtain, it leaves the true question of how to evolve a Galarian Slowpoke into the Isle of Armor Exclusive Galarian Slowbro. In order to obtain a Galarian Slowbro, players will first have to search and find eight Galarica Twigs. These are also a pretty common item, found at the base of most trees in the Isle of Armor. Once you have eight Galarica Twigs, head to the small island just off the shore where you first arrived on the Isle of Armor. Here, you will find a young lady that will be willing to turn your eight Galarica Twigs into a Galarica Cuff. This is the item that players can use to evolve Galarian Slowpoke into Galarian Slowbro simply by accessing it within their bag and having Galarian Slowpoke within their Party. It's as easy as that!