Take a Pokémon, any Pokémon.
Well... not just any Pokémon. The one you pick will have to be a Brokémon!
In order to make a Brokémon, you'll have to:
1. Take a Pokémon with a long 'o' sound in its name, like Totodile.
2. Replace the long 'o' sound with 'bro' to make something like Brotodile.
3. You've made a Brokémon!
Once we run out of Pokémon with long 'o' sounds in their name... well, we'll thing of something else to add to the Brokédex. But for now, brocreate, I guess?
(Yeh, Brotodile is already one.)