HELP!! install_parse_failed_no_certificates for android

[javiera.ramirez]

Hi, i´m Javiera and i´m making my own smartphone aplicattion, but i have the following error : install_parse_failed_no_certificates when i´m trying to install the app on the cellphone with android. I've been investigate this problem, and i found that this it's because i have to certificate the app, but i don´t know how to do this...

please help!!!!