Datasets are a collection of data streams, tags and descriptions which can be published in order to share the dataset and its content with other users of the Dataspace.
To create a Dataset, connect to your node, click the "+" symbol and select "New Dataset".
Fill in the required information and add tags, which will be shown to data consumers during the subscription process.
Add however many data sources and streams/events are needed for the use case. The IDs are required to publish data so write them down or come back to the Dataset whenever they are needed.
Once you are done, hit "Generate Dataset" to finish the creation process. The Dataset should now be visible in "My Datasets".
Publishing a Dataset makes a certain timeframe of the data available for selected data consumers in the Dataspace.
In order to publish the Dataset, head once again to "My Datasets", select the Dataset and hit the "Add Publication" button.
Follow the instructions of the publication dialog and confirm your choices to make the Dataset available to data consumers in the Dataspace.