Thanks for your posting! The relationship between templates and fields is configured on the respective field pages. For example, if you want to add a “Test Case (Steps)” template and assign the separated steps field to this template, you can edit the separated steps field as follows (when editing the field):
You can repeat this per template and field as needed.
The field overview on the template form is only to show the fields that apply to this template and the actual configuration is done on the field forms.
It’s also planned to add a migration guide for updated installations and I already documented the process here:
I hope this helps!