I want to store only my raw data in my blob storage, and I want to create a Hyperdataset with all the artificats, metrics, frames,

Yes that's exactly how it works.
None

This line adds a reference to raw file (local/remote)
https://github.com/allegroai/clearml/blob/1b474dc0b057b69c76bc2daa9eb8be927cb25efa[…]es/hyperdatasets/data-registration/register_dataset_with_roi.py

This line adds some metadata
https://github.com/allegroai/clearml/blob/1b474dc0b057b69c76bc2daa9eb8be927cb25efa[…]es/hyperdatasets/data-registration/register_dataset_with_roi.py

This arguments will upload the raw data, if you do not provide it, it will assume the link point to an existing file already (i.e. no need to upload)
https://github.com/allegroai/clearml/blob/1b474dc0b057b69c76bc2daa9eb8be927cb25efa[…]es/hyperdatasets/data-registration/register_dataset_with_roi.py