Q: How to set up my apple tv in mexico with wifi

do you choose the correct SSID and put in the correct encryption password ?

do you have access to free internet stuff such as youtube and trailers and the likes ?

have you turned on iTunes sharing in iTunes on your computer and allowed the ports in the firewall ? TCP and UDP ports used by Apple software products - Apple Support

this need to be done in both the computers firewall and in your wifi router if it's security is set to stright 

double post