You will see a hierarchic tree in the interface, representing the structure of your Dynamics instance. This contains the primary entities, their fields and their relationships to other entities (N:1, 1:N and N:N). Additionally, there are content controls that allow you to further modify your text (loop, group, filter, format, calculations).
The top-item will be the Dynamics instance the user can choose, and then the applications available in the instance.
Upon double-clicking on a field, you can map it in the wysiwyg editor on the cursor place. The mapped fields should be between [[ ]] or curly brackets {}, so that this is a unique identifier.
For each field you have mapped there will be a pane (settings) in the interface where you will have the option to format it as desired (string, number, currency).
In a pane that is placed under the data tree, you can also add a reference record from Dynamics where the field value is represented. Fields with the same primary entity inherit the selected reference record.
Reference Record
You need to be able to select a record from Dynamics 365 which contains data so you can test this on the mapped fields or use this record to show the specific data in the webpage. This record is always based on a primary entity with values for all the fields in the entities and its relations.
For each primary entity of the mapped fields you need to be able to select reference records that correspond to the values you wish to map in your content. The reference records are records from your Dynamics instance that are representing the values you want to display in your webpage.
You can also use this to see the values of the mapped fields and how they will be displayed in your webpage.
In the interface you will be able to create a reference record based on the primary entity of the fields you are mapping. You can add a reference record in the pane of the settings of a mapped field.
Additionally, upon selecting a field in your data tree, you see the value of that field that corresponds to the record you selected as reference. The field value can be seen in the settings pane.