First, choose for scoped access. This way you can choose what permissions your app will have, and thus what your app can do (read, write, delete...). Next, you can choose for either App folder (if you want your app to only have access to a specific folder) or Full Dropbox access (if your app can access everything in your Dropbox). If you choose for the former option, make sure to put the files you want to access into this folder. This folder will automatically be created and named after your app name. Finally, you can choose this name of your app.