Like most new iterations of the Pokémon franchise, Pokémon Scarlet and Violet introduce several new ways to evolve your Pokémon. Most of them are pretty straightforward, though there's one set of evolutions in particular that don't seem to work as advertised. These involve the Let's Go mechanic of the games.
Bramblin, Pawmo, and Rellor all evolve using the Let's Go function in Pokémon Scarlet and Violet, which, more specifically, involves walking your Pokémon outside their Poké Balls. In each case you need to release your lead Pokémon with the ZR button, then travel 1,000 steps with your buddy. Do that, then level up your Pokémon, and it should evolve into its next form.
There's an emphasis on should in that sentence because the Let's Go evolution doesn't work as you might expect. As of this writing it appears that the step count toward evolution resets itself each time your Pokémon returns to its Poké Ball. In other words, you need to travel 1,000 steps with your Pokémon outside of its Poké Ball, without letting it go back in, before it will evolve.
This is a bit tougher than it sounds, and can be quite frustrating if you get it wrong. Here are the steps you should follow when trying to evolve your Bramblin, Pawmo, or Rellor:
- Choose a town or city location with lots of long, uninterrupted walkways or roads. Most towns are decent for this purpose, so long as they don't have a ton of stairs. Mesagoza, Cortondo, Porto Marinada, and Levincia are all good, early-game examples of locations you can use.
- Once at the location, make sure you stay in the location. Don't wander out into areas with wild Pokémon that will interrupt your walking, and don't enter any buildings. Focus on evolving your Pokémon.
- Release the Pokémon you want to evolve with the ZR button. Don't use the R button, as it orders the Pokémon to attack, and it will return to the ball after a few seconds.
- Begin to walk along your chosen route. There are three walking speeds, and you want to find the sweet spot between the slowest and quickest. Tilting the control stick most of the way in the direction you want to go, but not fully, should do the trick. If you go too slowly this process will take a long time, and if you go too quickly your Pokémon will fall behind and return to its ball. Keep your Pokémon roughly by your side, and avoid stairs, buildings, or other obstacles that would cause the Pokémon to fall behind. If the Pokémon disappears from view behind you then you need to stop and let it catch up.
- Walk around with your Pokémon by your side for around ten minutes. If you reach the end of your route, turn around and walk back the way you came. Keep looping the safe area until you're roughly confident that you've taken a thousand steps. There's no sure way to tell besides trying to evolve your Pokémon, so the longer you can stand walking, the better.
- Once you're ready to evolve your Pokémon, either use a Rare Candy, XP Candy, or a few battles to level it up. If you took 1,000 steps successfully it will evolve into its next form once it levels up.
And that's that. So long as you give yourself plenty of walking time your Bramblin should evolve into a Brambleghast, your Pawmo into a Pawmot, and your Rellor into a Rabsca. And if it didn't work, well... better give yourself more walking time on your next attempt. Good luck!