Find where to submit a patent, and patent the Telephone as Bell creates that in 1876, and patent the internal gas combustion engine for cars.
Mostly need the engine because I’d probably fail to be able to explain properly how to get a phone working properly, I understand the concepts, but proving enough for a patent to hold up, not sure.

Congratulations, now I’ve become an enemy of the world because I’d have to use all the money I made from the engines to invest quickly in converting to renewable non gasoline based combustion engines to save the world from myself