Robots.txt.file

Hello,

I read something on how to create a robots.txt file. It tells me the file must be uploaded to the root accesible direcory of your site. My queiton is how would i add that coding Is in the htaccess and then add other suff below that. I am new to WordPress and FTP, This is my first time and I just have this issue to work out. Any help you can porvide would be very helpfull.