Dataset versions allow you to keep track of different versions of your dataset for export or model training. This creates a "locked in" or pinned snapshot of your dataset which you can use to train and tweak variations of your models. A dataset version is different than a model version which you will create at the model training step.
When a new version is created, the following attributes will be locked in your current version, and changes after that time will be applied to the next version:
In your dataset, navigate to the "Versions" tab.
Click "New Version"
In the modal, click "Create Version" to lock in your current dataset.