Изменение уровня SDK для Android Project

Я начал писать свое первое приложение для Android и выбрал SDK 2.0.1, еще до того, как у меня появился телефон Android. I wantto test the app on a phone that is Android 1.6. The app itself uses pretty simple stuff, so I'm sure its 1.6 compatible, but I want to change the SDK level from Eclipse.

The "default.properties" file in my project tree and naively tried to change from Android 6, but it isn't changeable, but if I try to change it it tells me to change the build.properties of the project. I don't know what that means. I'm not used to eclipse and am still fumbling around it.

I went to the project properties and clicked on "Java Build Path", but from there I don't know how to add,remove or edit the libraries.

Basically, I'm asking how to downgrade my project from inside eclipse, so I can export it to a compatible phone.