rebuild user managment in existing web-App

An existing application has six modules, the user administration module is to be made ​​new. The old pages are the design templates for the three new page (edit user, group, departments). On each side there are three button (new, edit, delete). The buttons open a form to input the data. Entries are saved locally and sent to the web service (API). All data are provided by a web service API. All results are in json format. The data must be stored locally so that the application works offline. The application is multilingual. The key for each text is already found on the web service API.