First things first, make sure you have an account on the Chargifi Platform, as you can't self-register for one. If you don't have one already, contact an Administrator in your company and get them to create one for you.
Once you have your account details, you can sign into the web application at app.chargifi.com and will then see a list of apps for you to choose from on the left-hand side menu.
For instance, if you are looking for the mobile app, you can download this from apps.chargifi.com. When you launch the app you will see a login screen so enter your details again and you are good to go!