I've had to do that and to be sure my pea brain didn't find it easy. There were a lot of steps. If I had to do it every day I guess it would get easier
What cloud platform do you plan to use? There may be some type of API provided that will expose a way to upload files to the cloud service and they could already have all the server-side code in place and you just have to pass either a file or a stream to the service. In the past what I did was save it out to the device then uploaded the file to the server.
The challenge with an app is that it is stateless. This doesn't happen with browser based apps. One way to handle this is using a token based approach to maintaining state. For example, Volt uses JWT (JSON Web Tokens). In order to upload files to a service, you will most likely need to successfully negotiate their auth system with your app.
If you find an easier way to do this and if you feel like sharing, that would be great!