[Other] How do I add new types in the Generation I games?

[The Puerto Rican Magnemite]

Greetings. I wanted to hack a few new types (the usual 'Dark,' 'Fairy,' and 'Metal' types, plus several others) into Pokémon Blue using Coolboyman's tutorial. Hacking the types that were already there went fine, but adding the types I wanted, even within the bounds of the blank spaces, but the game just went blank while a sound effect (probably the 'Pokémon caught!' effect) repeatedly plays.

Is there anything I need to do? I am already familiar with the ROM-hacking tools and programming in general, but I am still shaky on how the Pokémon games handle pointers. I am not good at navigating, much less interpreting, iimarckus' disassembly of Pokémon Red and Blue. I suspect that I have to make my own type table and repoint the game to the new table, but then there is the aspect of naming the new types.