When testing a new prompt, you may already have a set of examples you want to test against. Assuming you have already created a dataset for these examples (see Datasets if you still need to), you can easily add these examples to the playground.
In the playground, after you click
Add test case, a drawer will open, allowing you to select any of your
datasets to add to the playground. After selecting a specific collection, you can check all the
examples you want to add.