I don't get it. . . . They have two thumbs, but within reach of their thumbs are extra keys. They need these extra keys because there are a lot of characters i

I don't get it. . . . They have two thumbs, but within reach of their thumbs are extra keys. They need these extra keys because there are a lot of characters in their writing. They don't need more thumbs, because they only need to push one of these extra keys at a time. Do I need more pointer fingers if I need to use one of the Y, H, N, B, T, G, and V keys?