To top up your SPITCH account you have to go to the "MORE" tab and select "Finances". There you can choose whether you want to deposit or withdraw an € amount. As soon as you click on "Deposit", you can enter the amount of € you want to top up on your SPITCH account. There you can also choose your payment method.
Currently you can only use the Mobile App on Apple devices. We are working on offering SPITCH on Apple devices for Mobile-Web as well.