You need Premium or Premium Per user to work with Deployment Pipelines
This happens right at the beginning of the Deployment Pipeline process when you have just added Dev to the Pipeline and you need to deploy Test and Prod
Tip – Changing Data source Rules for Dataflow
You now need to deploy your dev dataflow which is connected to the dev database into Test. You cant change the data source rule until you have a data source to work with.

After deploy, the test dataflow is still against the dev data source (Azure SQL database)

Click Test Deployment Settings
Deployment Rules – Click on your dataflow
Data Source Rules – Change This (Your Dev Details) to this (Select and choose your Test SQL Server and Database)


And Save
The tip here is to then deploy your dataflow Dev to Test again. Only then will it use the new settings.
To check go back to the workspace and go to settings for the dataflow

Deploying Datasets that contain multiple data sets
This is specific to setting up Power BI With the Following Option

With this option set you can create smaller data sets, probably based on a star schema. Then if required you can connect to another data set. And then connect to more data sets and data. Without this option you can only connect to one data set.
This has changed from a Direct Query Connection (The standard way. 1 Data Set Only) to Live Query Connection (Analysis Services and Multiple data sets)

Tip- Move your hybrid data set after the original data sets

So here, what we can do is move the dataflows, and datasets A B and C at the same time.
Once completed move Star A B and C so it goes after the schemas its based on
Then do the report.
If you try and do them all together you will get errors.
So these are just a couple of tips to look out for when setting up your Pipelines for the first time. And if you use the setting that allows you to connect to multiple data sets.