Can I change the name of the folder containing my site

I am new to WP and I have things as follows:

I have and

all in the same server I need to move prueba to http://imesex.edu.mx as the main site in that folder or I can point the URL imesex.edu.mx to http://48horasdigital.com/prueba and move the folder blog to that location, I don’t know

The easier for me is to point the URL imesex.edu.mx to prueba and creat a link from my main menu to
but I don’t know how to do the external link from the main menu.

I’m sorry, I’m trying to learn and I’m 65 years old and is more difficult for me