How to implement a dowloaded Theme?

[Scree]

Exactly as the tittle of my question, how do you implement a downloaded Theme? I can't seem to find out how to do that anywhere..

[IntoRain]

File Manager > public_html > templates for files modifying or adding new folders

&&

phpMyAdmin > _themes > insert new for changestyle to be able to push it from the database (your folder name has to be the same as the one you put here)