You need to go in to the project(s) where you will be tracking the Dynamic Application data and 'switch' on the application. Go into a project, select Admin>Edit Project and towards the bottom check the box for your dynamic application. Now when you go out to your Application Tab and create new item, that project will appear. Repeat for any other projects.
To switch it on globally for all new projects moving forward, you can Edit the Project Type from the Admin zone and turn it on there.