hi
I download Spanish translation (es_ES.UTF-8) but it told me that it was for a older version and it might not work, but still did it. In the page that i give the e-mail and password is in spanish but when i enter to create milestones or tickets is in english
If it's a translation for an older release, it's possible that it's not complete. Go to Administration > Languages, find Spanish translation and make sure that all phrases are translated in all available dictionaries (language indexes for available modules).
Once you verify that translation is complete and that all phrases are translated, system should be properly localized. Before that, it's possible that it's just partially translated.
I download Spanish translation (es_ES.UTF-8) but it told me that it was for a older version and it might not work, but still did it. In the page that i give the e-mail and password is in spanish but when i enter to create milestones or tickets is in english