While using the new data table, you can update column properties such as Column Name, Column Description, API Field Name, and Data Type.
In order to update a dataset, you will first need to create a working copy of the dataset. If you are working in a derived view, this is not necessary.
Once you are in a working copy, you can click Edit > Edit Columns to launch a modal where you can edit all of your columns. You can use the Previous and Next buttons to scroll through each column on your dataset.
The column properties can be found in the first tab of the modal.
As you can see in the screenshot, there are four fields on this screen. To update, simply click in the text box and update the field you would like. You can scroll through each column and make your changes before clicking Save.
When changing a Data Type, a drop-down of available options will appear. Once you select the value, click the Convert Type button. Please note that this will close the modal and you will lose other unsaved changes.
Once your changes are made and saved, you can publish your working copy so that the changes are applied on the live dataset!