First, as with many others here, I gave you an example of how to do things, there is a lot of options to do what you want. I have just put the upload option because I had to upload a pdf to outsystems to be possible to test what you wanted. You just use what you need or think you need.
Change the tag for embed.

Second, I don't see any attribute on your entitys that is going to be used to store a pdf, how do you want to show a pdf if you are not storing any?
If you want to show a PDF from the database you need to have an attribute to save the PDF in the database, I advise you to be of data type binary data.
After that, have look again at my example, and see how do I convert the binary data pdf to base64 and how am I showing as a frame on the screen.
Let me know if I am wrong in something, I will be waiting for a reply! :)
Kind Regards,
Márcio