Modifications on a small social network android app

I have an android application (specifically social network) and everything going smooth. I want to add additional features: 1- Right now users need to log in in order to browse the app. I want browsing is open for everyone without the need for logging in. If someone want to post or comment then he should to login. 2- Now, there is no something called country in the app. I want the app have the country level. When opening the app for the first time, the app asks you what is your country so the content is filtered by the country. Also when user sign up he chose his country to save it into the database. Also, all posts should have the country category. 3- Posts should also have a new category called "classroom". when user sign up he choose his classroom. It is possible for users to browse or comment content of other classrooms. All modifications should be the same method the app now is written