@Sebastian_M Welcome to the community.
Are you uploading the file in the previous workflow action?
WeWeb (currently**) uploads the file to their CDN with a workflow action.
**I believe that WeWeb is working on updating the element so that you can just store the file into your database directly, but right now it goes into the WeWeb CDN first.
If you want to store the file in the S3 Storage, you are going to need to use the workflow action to upload the file to WeWeb CDN, and then get it into S3.
The result of the upload action contains the URL of the file.
I’m not familiar with S3, but do they have an endpoint that you can supply a URL to that will then take the file and bring it into S3?
If so, that would be something you could just do on the next workflow action.
If I’m understanding your question correctly, I think the above will work. And, checkout these links on the upload element:
Is that helpful?