Place the folder containing the 'basic config' file in the '/home/<user_account>/.config/' directory if you are using Linux, or the respective configuration folder depending on the operating system.
Yes, you can place another theme in this folder. In this example, the folder already contains a theme and the necessary configuration for importing it into the alacritty.toml file. You can add additional themes following a similar structure.
If you are using Linux, you can run this command in your console, provided that you have installed all the dependencies for Alacritty.
Otherwise, you can visit the official documentation at official doc https://github.com/alacritty/alacritty or refer to the man 5 alacritty command.