You should add extra properties of the type “attribute” to your XML. They should have the datasource property set pointing to your data source. Here’s an example from Data Grid 2:
<property key="datasource" type="datasource" isList="true">
<caption>Data source</caption>
<description/>
</property>
<property key="attribute" type="attribute" dataSource="../datasource" required="false">
<caption>Attribute</caption>
<description>Attribute is required if the column can be sorted or filtered</description>
<attributeTypes>
<attributeType name="String"/>
</attributeTypes>
</property>
In this configuration, attribute will be a ListAttributeValue. The link explains it more, but the code you would need in this example is like:
const attributeValue = this.props.attribute.get(this.props.datasource.items[0]);