If you'd like to retrieve fundamental data into Excel VBA, then please visit the link below. This is where you can find documentation, examples and tutorials for Eikon COM APIs for use in Microsoft Office.
The best way to explore the field names and parameters you can use to retrieve data through =TR function is by following Formula Builder wizard in Eikon Excel. In Thomson Reuters ribbon click on the leftmost button named Build Formula and follow the prompts. Once you've completed the wizard and are happy with the data retrieved into Excel worksheet by =TR function, the syntax used in =TR function is fairly straightforward to translate into syntax required for DEX2 COM library. If you need help with using Formula Builder wizard or =TR function, I would suggest you call your local Thomson Reuters Helpdesk. The Helpdesk representative can guide you through the wizard and =TR function.
Finally, I'm not sure what was the significance of the screenshot you included, but I'm afraid I have no idea what it illustrates. I cannot even tell what application this is. If you need assistance with whatever that screenshot represents, please elaborate on how you created this image.