Datatrees should possess sample data from your connected app's database, as shown below in italics, to provide a better sense of what the data looks like.
In some cases, sample data will be lacking or the datatree is incomplete (i.e. some of your fields in your app don't show up)
Sometimes, you don't see sample data such as for "Account Description" in the above example. This is because the data tree uses the first object that it can find, such as the first account in the list of accounts. Thus, when there is no sample data for a particular pill, it means that the particular field is left blank for that object.
As for the lack of fields, there can be many reasons why custom fields don't show up. You should try to connect/reconnect the recipe to your app. As Workato pulls your object's custom fields from your connected app, a re-connection gives you another try on pulling your custom fields out to the step.