AEMaaCS Asset upload process Design

Hi All,

Have below requirement which needs to be design for execution.

1. Initial, 3rd party app invoke 3-step process (initiate upload, uploadURI, completeUpload) to upload assets onto AEMaaCS.

2. Once upload of asset is complete onto cloud, AEM will quick start.

3. AEM needs to start processing custom metadata (comes as request attributes when upload request is made from front end).

4. After custom metadata is processed on Assets it needs to be replicated accordingly.

Can anyone let know how this can be design for achieving the use case specified.

Thanks in Advance.